A novel data-driven model for prediction and adaptive control of pH in raceway reactor for microalgae cultivation.

This work proposes a new data-driven model to estimate and predict pH dynamics in freshwater raceway photobioreactors. The resulting model is based purely on data measured from the reactor and divides the pH dynamics into two different behaviors. One behavior is described by the variation of pH due to the photosynthesis phenomena made by microalgae; and the other comes from the effect of CO2 injections into the medium for control purposes. Moreover, it was observed that the model parameters vary throughout the day depending on the weather conditions and reactor status. Thus, a decision tree algorithm is also developed to capture the parameter variation based on measured variables of the system, such as solar radiation, medium temperature, and medium level. The proposed model has been validated for a data set of more than 100 days during 10 months in a semi-industrial raceway reactor, covering a wide range of weather and system scenarios. Additionally, the proposed model was used to design an adaptive control algorithm which was also experimentally tested and compared with a classical fixed parameter control approach.

Chromatin Immunoprecipitation to Investigate H2A.Z Dynamics in Response to Environmental Changes.

DNA methylation and posttranslational modifications of histones instruct gene expression in eukaryotes. Besides canonical histones, histone variants also play a critical role in transcriptional regulation. One of the best studied histone variants in plants is H2A.Z whose removal from gene bodies correlates with increased transcriptional activity. The eviction of H2A.Z is regulated by environmental cues such as increased ambient temperatures, and current models suggest that H2A.Z functions as a transcriptional buffer preventing environmentally responsive genes from undesired activation. To monitor temperature-dependent H2A.Z dynamics, chromatin immunoprecipitation (ChIP) of H2A.Z-occupied DNA can be performed. The following protocol describes a quick and easy ChIP approach to study in vivo H2A.Z occupancy.

Study of pH and Thermodynamic Parameters via Circular Dichroism Spectroscopy of a Recombinant Human Lactoferrin.

The production of human recombinant proteins to be used for therapeutic or nutritional purposes must focus on obtaining a molecule that is as close as possible to the native human protein. This biotechnological tool has been documented in various studies published in recent decades, with lactoferrin being one of those that has generated the most interest, being a promising option for recombinant technology. However, stability studies including thermodynamic parameters have not been reported for recombinant lactoferrin (Lf). The objective of this work was to obtain the human recombinant protein using the yeast Komagataella phaffii to study structural changes modifying pH and temperature using circular dichroism spectroscopy (CD). Thermodynamic parameters such as ΔH, ΔS and Tm were calculated and compared with commercial human lactoferrin. We propose the potential use of CD and thermodynamic parameters as a criterion in the production of recombinant proteins to be used in the production of specialized recombinant proteins.

Modifications of long-term heart rate variability produced in an experimental model of diet-induced metabolic syndrome.

Metabolic syndrome (MetS) has been linked to a higher prevalence of cardiac arrhythmias, the most frequent being atrial fibrillation, but the mechanisms are not well understood. One possible underlying mechanism may be an abnormal modulation of autonomic nervous system activity, which can be quantified by analysing heart rate variability (HRV). Our aim was to investigate the modifications of long-term HRV in an experimental model of diet-induced MetS to identify the early changes in HRV and the link between autonomic dysregulation and MetS components. NZW rabbits were randomly assigned to control (n = 10) or MetS (n = 10) groups, fed 28 weeks with high-fat, high-sucrose diet. 24-hour recordings were used to analyse HRV at week 28 using time-domain, frequency-domain and nonlinear analyses. Time-domain analysis showed a decrease in RR interval and triangular index (Ti). In the frequency domain, we found a decrease in the low frequency band. Nonlinear analyses showed a decrease in DFA-α1 and DFA-α2 (detrended fluctuations analysis) and maximum multiscale entropy. The strongest association between HRV parameters and markers of MetS was found between Ti and mean arterial pressure, and Ti and left atrial diameter, which could point towards the initial changes induced by the autonomic imbalance in MetS.

Electrical performance enhancement of MHD microgenerators through the longitudinal shaping of the cross-section.

In the present work, the impact that the longitudinal shape of channels has on the current produced in the flow of a magneto-hydrodynamic microgenerator (MHDMG) is studied. The goal is to find the micro-channel geometry via modeling to maximize the current output for low Reynolds and Mach regimes. To carry out this study, a 3D dynamic numerical tool relying on the finite volume method was handled with the open-source software OpenFOAM. It is the base model to study the impact of intricate geometries on the ability to produce energy. An additional steady-state 2D analytical model was also developed to check some basic modeling assumptions. Both models have been experimentally validated on the simplest flow system having a constant square cross-section throughout. The results produced by both models cross-check very well and compare favorably with respect to experimental data. Hence, using the validated numerical tool, three shapes have been further investigated, namely, progressive (linear decrease of the cross-section), arc (parabolic decrease of the cross-section), and wavy (sinusoidal shape). It was found that the arc channel provides the greatest current output for the same volumetric flow. It is therefore the preferred choice for developing high current gain and more efficient MHDMG used in micro-scaled actuators and sensors.

Erratum: Building the foundation for equitable and inclusive research: Seed grant programs to facilitate development of diverse CBPR community-academic research partnerships - CORRIGENDUM.

[This corrects the article DOI: 10.1017/cts.2022.495.].

The International Consortium on Primary Graft Dysfunction: Redefining Clinical Risk Factors in the Contemporary Era of Heart Transplantation.

BACKGROUND: Primary graft dysfunction (PGD) is the leading cause of morbidity and mortality early after heart transplantation (HT). The International Consortium on PGD is a multicenter collaboration dedicated to identifying the clinical risk factors for PGD in the contemporary era of HT. The objectives of the current report were (1) to assess the incidence of severe PGD in an international cohort; (2) to evaluate the performance of the most strongly validated PGD risk tool, the RADIAL score, in a contemporary cohort; and (3) to redefine clinical risk factors for severe PGD in the current era of HT. METHODS: This is a retrospective, observational study of consecutive adult HT recipients between 2010 and 2020 in 10 centers in the United States, Canada and Europe. Patients with severe PGD were compared to those without severe PGD (comprising those with no, mild and moderate PGD). The RADIAL score was calculated for each transplant recipient. The discriminatory power of the RADIAL score was evaluated using receiver operating characteristic (ROC) analysis, and its calibration was assessed by plotting the percentage of PGD predicted vs that which was observed. To identify clinical risk factors associated with severe PGD, we performed multivariable mixed-effects logistic regression modeling to account for among-center variability. RESULTS: A total of 2746 patients have been enrolled in the registry to date, including 2015 (73.4%) from North America, and 731 (26.6%) from Europe; 215 participants (7.8%) met the criteria for severe PGD. There was an increase in the incidence of severe PGD over the study period (P value for trend by difference sign test = 0.004). The Kaplan-Meier estimate for 1-year survival was 75.7% (95% CI 69.4-80.9%) in patients with severe PGD as compared to 94.4% (95% CI 93.5-95.2%) in those without severe PGD (log-rank P value < 0.001). The RADIAL score performed poorly in our contemporary cohort and was not associated with severe PGD; it had an AUC of 0.53 (95% CI 0.48-0.58). In the multivariable regression model, acute preoperative dialysis (OR 2.41, 95% CI 1.31-4.43), durable left ventricular assist device support (OR 1.77, 95% CI 1.13-2.77), and total ischemic time (OR 1.20 for each additional hour, 95% CI 1.02-1.41) were associated with an increased risk of severe PGD. CONCLUSIONS: Our consortium has identified an increasing incidence of PGD in the modern transplant era. We identified contemporary risk factors for this early post-transplant complication, which confers a high mortality risk. These results may enable the identification of patients at high risk for developing severe PGD in order to inform peri-transplant donor and recipient management practices.

An artificial intelligence approach for identification of microalgae cultures.

In this work, a model for the characterization of microalgae cultures based on artificial neural networks has been developed. The characterization of microalgae cultures is essential to guarantee the quality of the biomass, and the objective of this work is to achieve a simple and fast method to address this issue. Data acquisition was performed using FlowCam, a device capable of capturing images of the cells detected in a culture sample, which are used as inputs by the model. The model can distinguish between 6 different genera of microalgae, having been trained with several species of each genus. It was further complemented with a classification threshold to discard unwanted objects while improving the overall accuracy of the model. The model achieved an accuracy of up to 97.27% when classifying a culture. The results demonstrate the effectiveness of the Deep Learning models for the characterization of microalgae cultures, it being a useful tool for the monitoring of microalgae cultures in large-scale production facilities while providing accurate characterization over a wide range of genera.

Transcription Factor Dynamics in Cross-Regulation of Plant Hormone Signaling Pathways.

Cross-regulation between hormone signaling pathways is indispensable for plant growth and development. However, the molecular mechanisms by which multiple hormones interact and co-ordinate activity need to be understood. Here, we generated a cross-regulation network explaining how hormone signals are integrated from multiple pathways in etiolated Arabidopsis (Arabidopsis thaliana) seedlings. To do so we comprehensively characterized transcription factor activity during plant hormone responses and reconstructed dynamic transcriptional regulatory models for six hormones; abscisic acid, brassinosteroid, ethylene, jasmonic acid, salicylic acid and strigolactone/karrikin. These models incorporated target data for hundreds of transcription factors and thousands of protein-protein interactions. Each hormone recruited different combinations of transcription factors, a subset of which were shared between hormones. Hub target genes existed within hormone transcriptional networks, exhibiting transcription factor activity themselves. In addition, a group of MITOGEN-ACTIVATED PROTEIN KINASES (MPKs) were identified as potential key points of cross-regulation between multiple hormones. Accordingly, the loss of function of one of these (MPK6) disrupted the global proteome, phosphoproteome and transcriptome during hormone responses. Lastly, we determined that all hormones drive substantial alternative splicing that has distinct effects on the transcriptome compared with differential gene expression, acting in early hormone responses. These results provide a comprehensive understanding of the common features of plant transcriptional regulatory pathways and how cross-regulation between hormones acts upon gene expression.

Building the foundation for equitable and inclusive research: Seed grant programs to facilitate development of diverse CBPR community-academic research partnerships.

Introduction: The effectiveness of community-based participatory research (CBPR) partnerships to address health inequities is well documented. CBPR integrates knowledge and perspectives of diverse communities throughout the research process, following principles that emphasize trust, power sharing, co-learning, and mutual benefits. However, institutions and funders seldom provide the time and resources needed for the critical stage of equitable partnership formation and development. Methods: Since 2011, the Detroit Urban Research Center, collaborating with other entities, has promoted the development of new community-academic research partnerships through two grant programs that combine seed funding with capacity building support from community and academic instructors/mentors experienced in CBPR. Process and outcomes were evaluated using mixed methods. Results: From 2011 to 2021, 50 partnerships received grants ranging from $2,500 to $30,000, totaling $605,000. Outcomes included equitable partnership infrastructure and processes, innovative pilot research, translation of findings to interventions and policy change, dissemination to multiple audiences, new proposals and projects, and sustained community-academic research partnerships. All partnerships continued beyond the program; over half secured additional funding. Conclusions: Keys to success included participation as community-academic teams, dedicated time for partnership/relationship development, workshops to develop equity-based skills, relationships, and projects, expert community-academic instructor guidance, and connection to additional resources. Findings demonstrate that small amounts of seed funding for newly forming community-academic partnerships, paired with capacity building support, can provide essential time and resources needed to develop diverse, inclusive, equity-focused CBPR partnerships. Building such support into funding initiatives and through academic institutions can enhance impact and sustainability of translational research toward advancing health equity.

Leaf endophytic microbiomes of different almond cultivars grafted to the same rootstock.

AIMS: We compared the bacterial endophytic communities of three genetically different almond cultivars that were all grafted on the same type of rootstock, growing side by side within a commercial orchard. METHODS AND RESULTS: We examined the diversity of leaf bacterial endophytes using cultivation-independent techniques and assessed the relative abundance of bacterial families. Two of these three cultivars were dominated by Pseudomonadaceae, while the bacterial composition of the third cultivar consisted mainly of Streptococcaceae. CONCLUSIONS: The experimental set up allowed us to analyse the impact of the shoot cultivar on endophytes, minimizing the influence of rootstock, biogeography, and cultivation status. Our data suggest that the shoot cultivar can shape the leaf endophytic community composition of almond trees. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results suggest that the shoot cultivar controls the composition of the foliar bacterial endophytic community of almonds. Overall, our results could provide a first step to develop strategies for a more sustainable almond agriculture.

Bilateral pericapsular nerves group (PENG) block for analgesia in pediatric hip surgery.

Effective management and control of peri- and postoperative pain in hip surgery is essential in order to minimize the use of opioids and their adverse effects. Effective regional analgesia for hip pain is made particularly challenging by the complex innervation of the hip joint. Standard regional techniques can be associated with complications, including incomplete anesthesia, hypotension, or lower limb weakness. We present the case of a 5-year-old girl with a history of infantile cerebral palsy who underwent bilateral varus derotation osteotomy and adductor tenotomy due to paralytic dislocation. She received bilateral PENG block and femoral cutaneous nerve block-a simple technique that covers all the nerves involved in the sensory innervation of the joint capsule without the need for multiple injections.

Complex interactions between nicotine and resveratrol in the Drosophila melanogaster wing spot test.

Nicotine (NIC) and resveratrol (RES) are chemicals in tobacco and wine, respectively, that are widely consumed concurrently worldwide. NIC is an alkaloid known to be toxic, addictive and to produce oxidative stress, while RES is thought of as an antioxidant with putative health benefits. Oxidative stress can induce genotoxic damage, yet few studies have examined whether NIC is genotoxic in vivo. In vitro studies have shown that RES can ameliorate deleterious effects of NIC. However, RES has been reported to have both antioxidant and pro-oxidant effects, and an in vivo study reported that 0.011 mM RES was genotoxic. We used the Drosophila melanogaster wing spot test to determine whether NIC and RES, first individually and then in combination, were genotoxic and/or altered the cell division. We hypothesized that RES would modulate NIC's effects. NIC was genotoxic in the standard (ST) cross in a concentration-independent manner, but not genotoxic in the high bioactivation (HB) cross. RES was not genotoxic in either the ST or HB cross at the concentrations tested. We discovered a complex interaction between NIC and RES. Depending on concentration, RES was protective of NIC's genotoxic damage, RES had no interaction with NIC, or RES had an additive or synergistic effect, increasing NIC's genotoxic damage. Most NIC, RES, and NIC/RES combinations tested altered the cell division in the ST and HB crosses. Because we used the ST and HB crosses, we demonstrated that genotoxicity and cell division alterations were modulated by the xenobiotic metabolism. These results provide evidence of NIC's genotoxicity in vivo at specific concentrations. Moreover, NIC's genotoxicity can be modulated by its interaction with RES in a complex manner, in which their interaction can lead to either increasing NIC's damage or protecting against it.

Hydrodynamic cavitation through a bio-inspired fast-closing plunger mechanism: experiments and simulations.

Experimental and numerical results are reported for the internal and external flow fields evolving in a bio-inspired snapping plunger. The experimental evidence underlines the nature of the dynamic-coupling between the processes taking place inside and outside the device. Two main structures dictate the properties of the external flow field: a strong jet which is followed by a vortex ring. Internally, complex patterns of cavitating structures are simultaneously produced in the chamber and the venturi-like conduit. We find the cavitation cycle to be suitably described by the Rayleigh-Plesset model and, thus, proceed to characterize the coupling of both fields in terms of the fluctuations of the velocity. All main parameters, as well as the energy released to the fluid during the collapse, are found to be within the same order-of-magnitude of previously known experimental results for isolated bubbles of comparable size.

Do Unhelpful Thoughts or Confidence in Problem Solving Have Stronger Associations with Musculoskeletal Illness?

BACKGROUND: Measures of unhelpful thoughts and distress correlate with the intensity of pain and the magnitude of incapability among people seeking musculoskeletal specialty care. In this evolving knowledge area, we want to be sure we have not neglected other important mental health factors. This study addressed how measures of confidence in problem solving as well as past and current ability to achieve goals account for variation in symptoms and capability independent of unhelpful thoughts and distress. QUESTIONS/PURPOSES: (1) Are measures of confidence in problem solving ability and past and current ability to achieve goals regarding future outcomes associated with variation in capability, independent of measures of symptoms of depression and anxiety (distress) and measures of unhelpful thoughts (worst-case thinking, negative pain thoughts)? (2) Are these measures independently associated with variation in pain intensity? (3) Are these measures associated with measures of symptoms of depression, symptoms of anxiety, and unhelpful thoughts? METHODS: Over a 7-month period during the pandemic, we enrolled sporadically from the offices of four surgeons treating patients who sought care for various upper and lower extremity conditions. We invited approximately 200 adult new and returning patients to participate (the number of invitations was not formally tracked) and 187 accepted. Thirty-one were excluded due to markedly incomplete entries (related to a problematic attempt to use the patient's cell phone to complete questionnaires as a pandemic work around), leaving 156 for analysis. Patients completed an 11-point ordinal rating of pain intensity, two measures of unhelpful thoughts (the Pain Catastrophizing Scale and the Negative Pain Thoughts Questionnaire), the Adult Hope Scale to measure past and current ability to achieve goals, the Personal Optimism and Self-Efficacy Optimism Scale to measure confidence in problem solving ability, the Patient-reported Outcomes Measurement Information System (PROMIS) computer adaptive test to measure symptoms of anxiety, the PROMIS computer adaptive test to measure symptoms of depression, and the PROMIS physical function computer adaptive test to assess the magnitude of capability. All questionnaires were validated in previous studies. We used bivariate analyses to identify factors associated with magnitude of capability, pain intensity, confidence in problem solving ability, and past and current ability to achieve goals. All factors with a p value of less than 0.1 were included in multivariable analyses to seek associations between these measures accounting for confounders. We reported partial η2 as a measure of effect size for all multivariable regression models. The following rules of thumb are used to interpret values for partial η2: a value of 0.01 = small, 0.06 = medium, and values of 0.14 and higher show large effect size. RESULTS: Greater capability was modestly associated with fewer negative pain thoughts (ß = -0.63 [95% CI -1.0 to -0.22]; standard error = 0.20; partial η2 = 0.06; p = 0.003) and no self-reported comorbidities (ß = 2.6 [95% CI 0.02 to 5.3]; standard error = 1.3; partial η2 = 0.03; p = 0.048) after controlling for education, symptoms of depression and anxiety, worst-case thinking, as well as past and current ability to achieve goals. In a similar multivariable model, greater pain intensity was modestly associated with greater worst-case thinking (ß = 0.33 [95% CI 0.20 to 0.45]; standard error = 0.06; partial η2 = 0.16; p < 0.001) and established patients (ß = -1.1 [95% CI -1.8 to -0.31]; standard error = 0.38; partial η2 = 0.05; p = 0.006). In another similar multivariable model, having more confidence in problem solving ability had a limited association with higher ratings of past and current ability to achieve goals (ß = 0.15 [95% CI 0.09 to 0.21]; standard error = 0.03; partial η2 = 0.13; p < 0.001). In a final multivariable model, lower past and current ability to achieve goals was independently associated with having greater symptoms of depression (ß = -0.45 [95% CI -0.67 to -0.23]; standard error = 0.11; partial η2 = 0.1; p < 0.001) and more negative pain thoughts (ß = -0.49 [95% CI -0.89 to -0.09]; standard error = 0.20; partial η2 = 0.04; p = 0.02). CONCLUSION: The observation that unhelpful thoughts about symptoms are more strongly associated with symptom intensity than past and current ability to achieve goals and confidence in problem solving ability add to the evidence that attentiveness to unhelpful thinking is an important aspect of musculoskeletal health. Musculoskeletal specialists can prioritize communication strategies such as relationship building and motivational interviewing that develop trust and facilitate reorientation of common unhelpful thoughts. LEVEL OF EVIDENCE: Level II, prognostic study.

Tasa de mortalidad por síndrome de dependencia del alcohol 2016-2020 en Chile / Alcohol use disorder-related mortality rate 2016-2020 in Chile

Introducción: El consumo de alcohol es un problema a nivel mundial. En Chile es la droga más consumida, y en cantidades mayores que otros países de la región. Debido a la alta prevalencia y la gran cantidad de complicaciones asociadas, se describió la tasa de mortalidad por síndrome de dependencia del alcohol (SDA) entre los años 2016-2020 en Chile. Materiales y métodos: Estudio observacional, ecológico y descriptivo. La población correspondió a todos los fallecidos por SDA como causa básica en Chile entre 2016-2020 utilizando fuente Departamento de Estadísticas e Información de Salud. Se calculó la tasa de mortalidad según sexo, grupo etario y región con un total de 710 personas. Resultados: Durante el período 2016-2020 se observó un aumento de la tasa de mortalidad principalmente en 2020. Respecto al sexo, predominó la tasa de mortalidad en hombres. El grupo etario con mayor tasa de mortalidad fue el de 65-79. El promedio más alto de la tasa de mortalidad entre los años 2016 y 2020 es el de la región de Los Lagos (2,09) y una desviación estándar de (1,05). Discusión: Resulta interesante que la tasa de mortalidad promedio atribuible al alcohol es menor en Chile y Estados Unidos que en otros países de América. Tanto en Chile como en Argentina y Cuba la tasa de mortalidad es mayor en hombres, sin embargo, en relación al rango etario, el predominio de las tasas varía en la región.

Introduction: Alcohol consumption is a worldwide problem that has been steadily increasing. Chile is among the countries with the highest alcohol consumption per capita in Latin America. Due to the high prevalence and the large number of associated complications, we described the mortality rate due to alcohol dependence syndrome (ADS) between the years 2016-2020 in Chile. Material y methods: Observational, ecological and descriptive study. The population corresponded to all deaths due to ADS as a basic cause in Chile between 2016-2020 using source Department of Health Statistics and Information. The mortality rate was calculated according to sex, age group and region with a total of 710 people. Results: During the period 2016-2020, an increase in the mortality rate was observed mainly in 2020. Regarding sex, the mortality rate was predominantly in men. The age group with the highest mortality rate was 65-79. The highest average mortality rate between 2016 and 2020 is that of the Los Lagos region (2,09) and a standard deviation of (1,05). Discussion: Interestingly, the average alcohol-attributable mortality rate is lower in Chile and the United States than in other countries in the Americas. In Chile as well as in Argentina and Cuba, the mortality rate is higher in men, however in relation to age range, the predominance of rates varies across the region.

Teaching Control during the COVID-19 Pandemic.

This paper aims to analyze some different solutions that were adopted in control education activities during the pandemic. The authors of this paper are educators in the control education field from different countries on all the continents, who have developed a questionnaire with the idea of collecting data about the COVID-19 pandemic impact on the control education activities. The main objective is to study the diverse alternatives that were used worldwide to perform the online educational activities during that period, such as methodologies, tools, learning management systems (LMS), theoretical exercises, laboratory experiments, types of exams, simulators, software for online lecturing, etc. As a result, comparisons between pre-and during-pandemic educational resources and methods are performed, where useful ideas and discussions are given for the control education community.

Bilateral pericapsular nerves group (PENG) block for analgesia in pediatric hip surgery. / Bloqueo bilateral del grupo de nervios pericapsulares (PENG) como analgesia en cirugía de cadera infantil.

Effective management and control of peri- and postoperative pain in hip surgery is essential in order to minimize the use of opioids and their adverse effects. Effective regional analgesia for hip pain is made particularly challenging by the complex innervation of the hip joint. Standard regional techniques can be associated with complications, including incomplete anesthesia, hypotension, or lower limb weakness. We present the case of a 5-year-old girl with a history of infantile cerebral palsy who underwent bilateral varus derotation osteotomy and adductor tenotomy due to paralytic dislocation. She received bilateral PENG block and femoral cutaneous nerve block - a simple technique that covers all the nerves involved in the sensory innervation of the joint capsule without the need for multiple injections.

Characterization of Erwinia gerundensis A4, an Almond-Derived Plant Growth-Promoting Endophyte.

The rapidly increasing global population and anthropogenic climate change have created intense pressure on agricultural systems to produce increasingly more food under steadily challenging environmental conditions. Simultaneously, industrial agriculture is negatively affecting natural and agricultural ecosystems because of intensive irrigation and fertilization to fully utilize the potential of high-yielding cultivars. Growth-promoting microbes that increase stress tolerance and crop yield could be a useful tool for helping mitigate these problems. We investigated if commercially grown almonds might be a resource for plant colonizing bacteria with growth promotional traits that could be used to foster more productive and sustainable agricultural ecosystems. We isolated an endophytic bacterium from almond leaves that promotes growth of the model plant Arabidopsis thaliana. Genome sequencing revealed a novel Erwinia gerundensis strain (A4) that exhibits the ability to increase access to plant nutrients and to produce the stress-mitigating polyamine spermidine. Because E. gerundensis is known to be able to colonize diverse plant species including cereals and fruit trees, A4 may have the potential to be applied to a wide variety of crop systems.

The use of photoperiod-treated bucks to induce a "male effect" does not compensate for the negative effects of nutritional restriction of the females in Mediterranean goats.

This work examined the effect of acute nutritional restriction or supplementation one week before male introduction on the reproductive performances of the "male effect" when using photostimulated or control males in goats. On 22 March, 84 anoestrous does were placed with photostimulated bucks or with bucks which had received no treatments. One week before male introduction, the females were provided with different nutritional regimes: Supplemented, restricted or control females. The non-esterified fatty acids (NEFAs) and Insulin Growth Factor-1 (IGF-1) concentrations were measured in the same samples. Fecundity, fertility, prolificacy and productivity were also determined. No interaction between both sources of variation was observed in any of the reproductive variables studied. Treatment of the bucks increased the percentage of females expressing behavioural oestrous associated with ovulation (71% vs 90% for Natural and Photo groups, respectively, P < 0.05). The Supplemented females showed higher ovulation rate than Restricted females (1.77 ± 0.13 vs 1.05 ± 0.05, P < 0.001), fecundity (71% vs 43%, P < 0.05); fertility (76% vs 29%, P < 0.05) and productivity (1.00 ± 0.15 vs 0.29 ± 0.11 kids per female, P < 0.01). In the Supplemented females, the higher reproductive results could be due to the lower NEFAs and higher IGF-1 concentrations at ovulation and at the time of oestrus compared to the Restricted females. Thus, the present experiment results demonstrate that nutrition is an important factor in the response to the "male effect" at Mediterranean latitudes, and its negative effect cannot be counterbalanced by using photostimulated bucks.