Population dynamics of the long-snouted seahorse (Hippocampus guttulatus Cuvier, 1829) in the Mar Menor coastal lagoon.

A 10-year monitoring program was developed to quantify the population dynamics of the long-snouted seahorse population in the Mar Menor coastal lagoon. Based on 985 underwater visual censuses, we estimated the long-snouted seahorse (Hippocampus guttulatus Cuvier, 1829) population size in the Mar Menor lagoon and its reduction in size in the last decades, as well as the effect of eutrophication crises in 2016 and 2019 on the species. The annual recruitment for the 2013-2020 period was estimated by comparing the relative abundance of early seahorse life stages in the ichthyoplankton. The density ranged from 0.0458 specimens/m3 at the beginning of the sampling period to 0.0004 at the end, showing a statistically significant difference between the three analyzed periods (Hgl=2 = 14.0, p = 0.001). The long-snouted seahorse population from the Mar Menor lagoon exemplifies the impact of fishing activities and human pressure, especially euxinic episodes and habitat destruction. As a result of this, the Mar Menor population has decreased from several million specimens to a few thousand, in only three decades. This species showed considerable resilience, the seahorse population began to recover once fishing activity stopped. In contrast, the long-snouted seahorse showed high vulnerability to habitat loss and an episodic flooding event. Adult seahorses showed preferences for highly complex habitats, especially Caulerpa prolifera-Cymodocea nodosa mixed meadows and habitats of high complexity and anthropogenic origin, such as harbors, jetties, or breakwaters. In contrast, juvenile seahorses preferred monotonous seabeds with low complexity, such as the sandy beds that are characteristic of the Mar Menor lagoon littoral.

Effect of Mercaptosuccinic Acid Stabilizer Agent on the Optical Properties of Colloidal CdTe Quantum Dots.

In the present work, we report on the positive effect of mercaptosuccinic acid (MSA) stabilizer agent on the optical features of colloidal CdTe quantum dots (QDs). With this aim, we performed some spectroscopic measurements such as steady-state absorption and fluorescence, fluorescence quantum yield and time-resolved photoluminescence for five MSA-capped CdTe QD samples with different synthesis times. The first general aspect to highlight is that the QDs' average size increased with synthesis time (from 30 to 150 min) while the size dispersion decreased due to the Ostwald ripening mechanism. Second, comparing the optical properties of CdTe QDs obtained from the same synthesis route, we show that MSA stabilizer agent enhanced the optical properties of CdTe QDs as compared with other widely used stabilizer agents such as GSH and TGA. We ascribe this outcome to reduction of the number of surface defects of the CdTe QDs because the MSA stabilizer agent decreases the growth rate of nanocrystals, causing an improvement in their surface quality. In the light of Fermi's golden rule, we observed that for longer synthesis time the optical properties of CdTe QDs increases due to the enhancement of the direct radiative recombination rate of electrons and holes and decrease in the decay rate for core states. Finally, we investigated the pH-dependent fluorescence and demonstrated the similar behaviour in acidic range between MSA-capped CdTe and mercaptocarboxylates-capped CdTe.

Selecting black-spot resistant papaya genotypes derived from backcrossing and hybrids.

Papaya crop is important to Brazilian agribusiness. However, the expansion of papaya cultivation in the country is affected by the absence of commercial cultivars presenting good disease resistance. The black-spot caused by the fungus Asperisporium caricae is the most damaging foliar disease affecting Brazilian papaya crops. The use of genetically resistant cultivars is a promising strategy to reduce the dependence of papaya crops on fungicides. A field split-plot experiment was carried out in the municipality of Linhares, Espírito Santo State, and included 20 hybrids derived from the cross between 14 superior lines and four elite genotypes ('SS72/12', 'SEKATI', 'JS/12' and '41/7'), two commercial cultivars ('Golden' and 'Tainung 01'), and the superior line '36/7', which were evaluated for resistance to black-spot in the fruits and leaves. The treatments were arranged in a randomized block design with six repetitions of three plants per plot. The incidence and severity of black spot in the fruits and leaves were evaluated at three different times in the 2015-2016 crop season. Lines 4, 9, 21, and the parent SEKATI were notable for their capacity to reduce disease severity in the leaves and fruits. Lines 1, 2, 9, 16, and 19, and the parents 'SEKATI' and 'SS-72/12' had reduced disease incidence in their fruits. The most resistant hybrids 'SS-72/12 X 4', 'SS-72/12 X 6', 'SEKATI X 1', 'SEKATI X 2', 'SEKATI X 6', 'SEKATI X 9', and 'SEKATI X 20' presented negative heterosis values for improved black-spot resistance. The current study allowed the selection of black-spot resistant genotypes and hybrids, which presented a significantly reduced disease index in the field.

Multivariate approach in popcorn genotypes using the Ward-MLM strategy: morpho-agronomic analysis and incidence of Fusarium spp.

The multivariate analyses are useful tools to estimate the genetic variability between accessions. In the breeding programs, the Ward-Modified Location Model (MLM) multivariate method has been a powerful strategy to quantify variability using quantitative and qualitative variables simultaneously. The present study was proposed in view of the dearth of information about popcorn breeding programs under a multivariate approach using the Ward-MLM methodology. The objective of this study was thus to estimate the genetic diversity among 37 genotypes of popcorn aiming to identify divergent groups associated with morpho-agronomic traits and traits related to resistance to Fusarium spp. To this end, 7 qualitative and 17 quantitative variables were analyzed. The experiment was conducted in 2014, at Universidade Estadual do Norte Fluminense, located in Campos dos Goytacazes, RJ, Brazil. The Ward-MLM strategy allowed the identification of four groups as follows: Group I with 10 genotypes, Group II with 11 genotypes, Group III with 9 genotypes, and Group IV with 7 genotypes. Group IV was distant in relation to the other groups, while groups I, II, and III were near. The crosses between genotypes from the other groups with those of group IV allow an exploitation of heterosis. The Ward-MLM strategy provided an appropriate grouping of genotypes; ear weight, ear diameter, and grain yield were the traits that most contributed to the analysis of genetic diversity.

Genetic control and combining ability of agronomic attributes and northern leaf blight-related attributes in popcorn.

The present study was conducted to investigate the genetic control and to estimate the general and specific combining abilities of popcorn for agronomic attributes and attributes related to resistance to northern leaf blight (NLB). The 56 hybrids (F1 and reciprocals), together with the eight parent lines and six controls, were evaluated in two harvests, in a randomized-block design with four replications. Dominance components were more expressive than the additive components for grain yield and expression of resistance, and hybridization was the most suitable option for obtaining resistant and productive genotypes. For grain yield, popping expansion, and resistance to NLB, there was no significance for reciprocal effects, which indicates that the direction in which the cross is performed does not interfere with the hybrid's performance. Then, the superior hybrids recommended for more profitable growth were P8 x L61, L61 x L76, and L61 x L77.

Selecting elephant grass families and progenies to produce bioenergy through mixed models (REML/BLUP).

Brazil has great potential to produce bioenergy since it is located in a tropical region that receives high incidence of solar energy and presents favorable climatic conditions for such purpose. However, the use of bioenergy in the country is below its productivity potential. The aim of the current study was to select full-sib progenies and families of elephant grass (Pennisetum purpureum S.) to optimize phenotypes relevant to bioenergy production through mixed models (REML/BLUP). The circulating diallel-based crossing of ten elephant grass genotypes was performed. An experimental design using the randomized block methodology, with three repetitions, was set to assess both the hybrids and the parents. Each plot comprised 14-m rows, 1.40 m spacing between rows, and 1.40 m spacing between plants. The number of tillers, plant height, culm diameter, fresh biomass production, dry biomass rate, and the dry biomass production were assessed. Genetic-statistical analyses were performed through mixed models (REML/BLUP). The genetic variance in the assessed families was explained through additive genetic effects and dominance genetic effects; the dominance variance was prevalent. Families such as Capim Cana D'África x Guaçu/I.Z.2, Cameroon x Cuba-115, CPAC x Cuba-115, Cameroon x Guaçu/I.Z.2, and IAC-Campinas x CPAC showed the highest dry biomass production. The family derived from the crossing between Cana D'África and Guaçu/I.Z.2 showed the largest number of potential individuals for traits such as plant height, culm diameter, fresh biomass production, dry biomass production, and dry biomass rate. The individual 5 in the family Cana D'África x Guaçu/I.Z.2, planted in blocks 1 and 2, showed the highest dry biomass production.

Learning from magnetotactic bacteria: A review on the synthesis of biomimetic nanoparticles mediated by magnetosome-associated proteins.

Much interest has gained the biomineralization process carried out by magnetotactic bacteria. These bacteria are ubiquitous in natural environments and share the ability to passively align along the magnetic field lines and actively swim along them. This ability is due to their magnetosome chain, each magnetosome consisting on a magnetic crystal enveloped by a lipid bilayer membrane to which very unique proteins are associated. Magnetotactic bacteria exquisitely control magnetosome formation, making the magnetosomes the ideal magnetic nanoparticle of potential use in many technological applications. The difficulty to scale up magnetosome production has triggered the research on the in vitro production of biomimetic (magnetosome-like) magnetite nanoparticles. In this context, magnetosome proteins are being used to mediate such in vitro magnetite precipitation experiments. The present work reviews the knowledgement on the magnetosome proteins thought to have a role on the in vivo formation of magnetite crystals in the magnetosome, and the recombinant magnetosome proteins used in vitro to form biomimetic magnetite. It also summarizes the data provided in the literature on the biomimetic magnetite nanoparticles obtained from those in vitro experiments.

Selection index based on the relative importance of traits and possibilities in breeding popcorn.

One of the major difficulties faced by popcorn breeders is the negative correlation between popping expansion (PE) and grain yield (GY). It is necessary to overcome this difficulty to obtain promising genotypes. One helpful tool in this process is a selection index because it allows multiple features of interest to be selected. Thus, the present study proposes a new and comprehensive selection index applied in 169 half-sib families in UEM-Co1 and UEM-Co2 composites during two cycles of recurrent selection. An experiment was conducted in a 13 x 13 lattice square in the 2004/2005 and 2006/2007 crop years in Maringá, Paraná State, and PE and GY were evaluated. To calculate Fi statistics, the following relative importance (RI) assignments were used: 0.5 for both PE and GY, and 0.70 and 0.30 for PE and GY, respectively. Families were classified according to Fi values such that Fi = 0 indicated that genotypes met the average of those selected by direct selection, Fi < 0 indicated that genotypes fell below the average of those selected, and Fi > 0 indicated that genotypes exceeded the average of those selected. Thus, desirable values of Fi were positive, indicating that the selected families were higher than those families that would be selected by direct selection for both traits. Therefore, we concluded that the novel Fi statistic was satisfactory for family selection because simultaneous and higher gains for both traits in both composites were obtained.

Inference of genetic diversity in popcorn S3 progenies.

Molecular markers are a useful tool for identification of complementary heterotic groups in breeding programs aimed at the production of superior hybrids, particularly for crops such as popcorn in which heterotic groups are not well-defined. The objective of the present study was to analyze the genetic diversity of 47 genotypes of tropical popcorn to identify possible heterotic groups for the development of superior hybrids. Four genotypes of high genetic value were studied: hybrid IAC 125, strain P2, and varieties UENF 14 and BRS Angela. In addition, 43 endogamous S3 progenies obtained from variety UENF 14 were used. Twenty-five polymorphic SSR-EST markers were analyzed. A genetic distance matrix was obtained and the following molecular diversity parameters were estimated: number of alleles, number of effective alleles, polymorphism information content (PIC), observed and expected heterozygosities, Shannon diversity index, and coefficient of inbreeding. We found a moderate PIC and high diversity index, indicating that the studied population presents both good discriminatory ability and high informativeness for the utilized markers. The dendrogram built based on the dissimilarity matrix indicated six distinct groups. Our findings demonstrate the genetic diversity among the evaluated genotypes and provide evidence for heterotic groups in popcorn. Furthermore, the functional genetic diversity indicates that there are informative genetic markers for popcorn.

Size control of in vitro synthesized magnetite crystals by the MamC protein of Magnetococcus marinus strain MC-1.

Magnetotactic bacteria are a diverse group of prokaryotes that share the unique ability of biomineralizing magnetosomes, which are intracellular, membrane-bounded crystals of either magnetite (Fe3O4) or greigite (Fe3S4). Magnetosome biomineralization is mediated by a number of specific proteins, many of which are localized in the magnetosome membrane, and thus is under strict genetic control. Several studies have partially elucidated the effects of a number of these magnetosome-associated proteins in the control of the size of magnetosome magnetite crystals. However, the effect of MamC, one of the most abundant proteins in the magnetosome membrane, remains unclear. In this present study, magnetite nanoparticles were synthesized inorganically in free-drift experiments at 25 °C in the presence of different concentrations of the iron-binding recombinant proteins MamC and MamCnts (MamC without its first transmembrane segment) from the marine, magnetotactic bacterium Magnetococcus marinus strain MC-1 and three commercial proteins [α-lactalbumin (α-Lac), myoglobin (Myo), and lysozyme (Lyz)]. While no effect was observed on the size of magnetite crystals formed in the presence of the commercial proteins, biomimetic synthesis in the presence of MamC and MamCnts at concentrations of 10-60 µg/mL resulted in the production of larger and more well-developed magnetite crystals (~30-40 nm) compared to those of the control (~20-30 nm; magnetite crystals grown protein-free). Our results demonstrate that MamC plays an important role in the control of the size of magnetite crystals and could be utilized in biomimetic synthesis of magnetite nanocrystals.

Genetic diversity of popcorn genotypes using molecular analysis.

In this study, we analyzed dominant molecular markers to estimate the genetic divergence of 26 popcorn genotypes and evaluate whether using various dissimilarity coefficients with these dominant markers influences the results of cluster analysis. Fifteen random amplification of polymorphic DNA primers produced 157 amplified fragments, of which 65 were monomorphic and 92 were polymorphic. To calculate the genetic distances among the 26 genotypes, the complements of the Jaccard, Dice, and Rogers and Tanimoto similarity coefficients were used. A matrix of Dij values (dissimilarity matrix) was constructed, from which the genetic distances among genotypes were represented in a more simplified manner as a dendrogram generated using the unweighted pair-group method with arithmetic average. Clusters determined by molecular analysis generally did not group material from the same parental origin together. The largest genetic distance was between varieties 17 (UNB-2) and 18 (PA-091). In the identification of genotypes with the smallest genetic distance, the 3 coefficients showed no agreement. The 3 dissimilarity coefficients showed no major differences among their grouping patterns because agreement in determining the genotypes with large, medium, and small genetic distances was high. The largest genetic distances were observed for the Rogers and Tanimoto dissimilarity coefficient (0.74), followed by the Jaccard coefficient (0.65) and the Dice coefficient (0.48). The 3 coefficients showed similar estimations for the cophenetic correlation coefficient. Correlations among the matrices generated using the 3 coefficients were positive and had high magnitudes, reflecting strong agreement among the results obtained using the 3 evaluated dissimilarity coefficients.

Experimental study of the efficacy of daptomycin for the treatment of cephalosporin-resistant pneumococcal meningitis.

OBJECTIVES: To determine the efficacy of daptomycin for the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis using in vitro and in vivo methods. METHODS: In vitro killing curves were determined with clinically achievable CSF antibiotic concentrations. In a rabbit model of pneumococcal meningitis, we studied the efficacy (Δ cfu/mL) of daptomycin used at 15 and 25 mg/kg, comparing it with ceftriaxone 100 mg/kg/24 h and ceftriaxone plus vancomycin 30 mg/kg/24 h over a 26 h period against two different strains: HUB 2349 and ATCC 51916, with MICs of 2 and 32 mg/L of cefotaxime/ceftriaxone, respectively. RESULTS: The penetration of daptomycin into CSF ranged between 9% and 11%. Daptomycin therapy achieved an excellent response, being bactericidal within 2 h of antibiotic administration. Against strain HUB 2349, daptomycin at both doses was as effective as ceftriaxone plus vancomycin. Against the highly resistant strain, daptomycin 25 mg/kg was significantly better than ceftriaxone plus vancomycin at 2 and 6 h. CONCLUSIONS: Daptomycin at standard doses, and especially at high doses, may be a useful alternative for the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis.

Efficiency of circulant diallels via mixed models in the selection of papaya genotypes resistant to foliar fungal diseases.

Diallel crossing methods provide information regarding the performance of genitors between themselves and their hybrid combinations. However, with a large number of parents, the number of hybrid combinations that can be obtained and evaluated become limited. One option regarding the number of parents involved is the adoption of circulant diallels. However, information is lacking regarding diallel analysis using mixed models. This study aimed to evaluate the efficacy of the method of linear mixed models to estimate, for variable resistance to foliar fungal diseases, components of general and specific combining ability in a circulant table with different s values. Subsequently, 50 diallels were simulated for each s value, and the correlations and estimates of the combining abilities of the different diallel combinations were analyzed. The circulant diallel method using mixed modeling was effective in the classification of genitors regarding their combining abilities relative to the complete diallels. The numbers of crosses in which each genitor(s) will compose the circulant diallel and the estimated heritability affect the combining ability estimates. With three crosses per parent, it is possible to obtain good concordance (correlation above 0.8) between the combining ability estimates.

Prospecting of popcorn hybrids for resistance to fall armyworm.

The fall armyworm, Spodoptera frugiperda, is the pest that causes the greatest economic losses for both common corn and popcorn crops, and the use of resistant plant genotypes is an important tool for integrated pest management. The goal of the present study was to evaluate the damage caused by S. frugiperda on single-cross popcorn hybrids under field conditions with natural infestation as well as to study the effect of 11 popcorn hybrids on the S. frugiperda life cycle under laboratory conditions. A completely randomized block design with 4 replicates was used for the field experiment, and a completely randomized design with 10 replicates was used for the laboratory experiment. In the field experiment, the damage caused by fall armyworm, grain yield, and popping expansion were quantified, and a diallel analysis was performed to select the best hybrids. For the laboratory experiment, caterpillars were obtained from laboratory cultures kept on an artificial diet and were fed with leaves from the 11 hybrids. Hybrids P7.0 x P9.4, P7.1 x P9.6, P7.2.0 x P9.3, P7.4.0 x P9.1 and P7.4.1 x P9.4 exhibited negative specific combining ability for injury by fall armyworm and positive specific combining ability for yield and popping expansion. In the laboratory experiment, the hybrids influenced the mean larval stage duration, mean larval mass, final larval mass, pupal stage duration, mean pupal mass, and adult longevity.

Ecophysiology and genetic structure of polar versus temperate populations of the lichen Cetraria aculeata.

We studied polar and temperate samples of the lichen Cetraria aculeata to investigate whether genetical differences between photobionts are correlated with physiological properties of the lichen holobiont. Net photosynthesis and dark respiration (DR) at different temperatures (from 0 to 30 °C) and photon flux densities (from 0 to 1,200 µmol m(-2) s(-1)) were studied for four populations of Cetraria aculeata. Samples were collected from maritime Antarctica, Svalbard, Germany and Spain, representing different climatic situations. Sequencing of the photobiont showed that the investigated samples fall in the polar and temperate clade described in Fernández-Mendoza et al. (Mol Ecol 20:1208-1232, 2011). Lichens with photobionts from these clades differ in their temperature optimum for photosynthesis, maximal net photosynthesis, maximal DR and chlorophyll content. Maximal net photosynthesis was much lower in Antarctica and Svalbard than in Germany and Spain. The difference was smaller when rates were expressed by chlorophyll content. The same is true for the temperature optima of polar (11 °C) and temperate (15 and 17 °C) lichens. Our results indicate that lichen mycobionts may adapt or acclimate to local environmental conditions either by selecting algae from regional pools or by regulating algal cell numbers (chlorophyll content) within the thallus.

Polarization effect on the two-photon absorption of a chiral compound.

In this report, we investigate the polarization effect (linear, elliptical and circular) on the two-photon absorption (2PA) properties of a chiral compound based in azoaromatic moieties using the femtosecond Z-scan technique with low repetition rate and low pulse energy. We observed a strong 2PA modulation between 800 nm and 960 nm as a function the polarization changes from linear through elliptical to circular. Such results were interpreted employing the sum-over-essential states approach, which allowed us to model the 2PA circular-linear dichroism effect and to identifier the overlapping of the excited electronic states responsible by the 2PA allowed band.

Femtosecond laser induced synthesis of Au nanoparticles mediated by chitosan.

This paper reports the synthesis of Au nanoparticles by 30-fs pulses irradiation of a sample containing HAuCl4 and chitosan, a biopolymer used as reducing agent and stabilizer. We observed that it is a multi-photon induced process, with a threshold irradiance of 3.8 × 10(11) W/cm2 at 790 nm. By transmission electron microscopy we observed nanoparticles from 8 to 50 nm with distinct shapes. Infrared spectroscopy indicated that the reduction of gold and consequent production of nanoparticles is related to the fs-pulse induced oxidation of hydroxyl to carbonyl groups in chitosan.

Temperature effect on the two-photon absorption spectrum of all-trans-ß-carotene.

In this report, we investigate the influence of temperature on the two-photon absorption (2PA) spectrum of all-trans-ß-carotene using the femtosecond white-light-continuum Z-scan technique. We observed that the 2PA cross-section decreases quadratically with the temperature. Such effect was modeled using a three-energy-level diagram within the sum-over-essential states approach, assuming temperature dependencies to the transition dipole moment and refractive index of the solvent. The results show that the transition dipole moments from ground to excited state and between the excited states, which governed the two-photon matrix element, have distinct behaviors with the temperature. The first one presents a quadratic dependence, while the second exhibits a linear dependence. Such effects were attributed mainly to the trans→cis thermal interconversion process, which decreases the effective conjugation length, contributing to diminishing the transition dipole moments and, consequently, the 2PA cross-section.

Antiplatelet therapies are associated with hematoma enlargement and increased mortality in intracranial hemorrhage.

OBJECTIVE: Antiplatelet therapy (AT) is increasingly used for treating or preventing vascular diseases, especially as a consequence of population aging. However, the risks may sometimes outweigh the benefits, mostly in relation to intracranial hemorrhage (ICH). Our aim was to determine whether AT is associated with hematoma enlargement and increased mortality in ICH. DESIGN: A prospective, observational cohort study. SETTING: The Intensive Care Unit (ICU) of Arrixaca University Hospital (Murcia, Spain). PATIENTS: We studied 156 patients admitted with non-traumatic ICH between January 2006 and August 2008. INTERVENTIONS: None. MAIN VARIABLES: Demographic data, medical history and clinical and laboratory parameters were recorded, along with hematoma volume upon admission and after 24h, and mortality. RESULTS: A total of 37 patients (24%) received AT. These subjects were older (69 ± 11 vs. 60 ± 15 years, p=0.001) and more frequently diabetic (38% vs. 15%, p=0.003) than those without AT. We detected no difference in hematoma volume upon admission between the two groups, though the volume was significantly greater after 24h in the AT group (66.7 [IQR 42-110] vs. 27 [4.4-64.6]cm(3), p=0.03), irrespective of surgical intervention. Moreover, hematoma volume increased by more than a third in AT-users (69% vs. 33%, p=0.002), and AT was the only significant predictor of hematoma enlargement. Patients on AT also had higher mortality during their ICU stay (78% vs. 45%, p<0.001). In addition, of the patients with hematoma enlargement, over one-third had higher overall mortality (62.5 vs. 28.8%, p=0.001). Independent risk factors for death were the Glasgow Coma Scale score, blood glucose upon admission, and AT. CONCLUSIONS: Our results show an association between AT and subsequent hematoma enlargement, as well as increased mortality in patients presenting with ICH who were receiving AT.

Predictors of Rehabilitation Referral Among Cardiovascular Surgical Patients.

Objective: Cardiovascular disease (CVD) continues to be the leading cause of mortality globally. Cardiac rehabilitation (CR) programs act by modifying the evolution of CVD and mortality; however, CR programs are under-used. The aim was to determine the profile of patients that received rehabilitation after cardiac surgery. Patients and Methods: A retrospective observational study was conducted from January 2017 to December 2017 at a single center. The study sample was chosen among patients admitted to the Intensive Care Unit of the Hospital Gregorio Marañón/Gregorio Marañón General University Hospital. Socio-demographic and clinical variables were collected. Results: In the present study, 336 patients underwent cardiac surgery of which 63.8% were men and 87.1% had ≥1 cardiovascular risk factors. Of the total cohort, 24.7% were operated for ischemic heart disease, 47.9% valvulopathy, 11% underwent combined surgery, 3.6% cardiac transplantation, 6.5% aneurysms, and 3.9% congenital disease. In-hospital respiratory rehabilitation was prescribed to all patients. Only 4.8% of the patients received motor rehabilitation and 13.8% were referred to CR. We found higher referral rates among patients with more cardiovascular risk factors, <65 years of age, and those undergoing coronary surgery and heart transplantation. Age, ischemic heart disease, and overweight were independent predictors of CR referral. Conclusion: The benefit of CR programs after cardiac surgery is widely described; however, the referral rate to CR remains low. It is crucial to optimize referral protocols for these patients.