增材制造Ti6Al4V合金的闪速等离子体电解氧化与在生理介质中的电化学行为

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PEO)处理及其电化学行为。通过短时间(<120 s)PEO处理(也称闪速PEO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改良的α-MEM溶液中,通过动电位极化曲线和电化学阻抗谱(EIS)评估了合金的电化学行为。与传统合金相比,AM合金中形成了细小的层片状α显微组织和层间小尺寸的β相颗粒,这促使了火花的产生,从而促进了PEO涂层的生长。闪速PEO涂层提高了传统合金和AM合金的耐腐蚀性,最薄的涂层(<3μm)提供了高达3倍的保护。AM Ti6Al4V由于其高的晶界密度,易受局部缝隙腐蚀的影响。而即使短至35 s的闪速PEO处理也足以成功避免这种情况。

Woody plant taxonomic,functional,and phylogenetic diversity decrease along elevational gradients in Andean tropical montane forests:Environmental filtering and arrival of temperate taxa

Mountains are paramount for exploring biodiversity patterns due to the mosaic of topographies and climates encompassed over short distances.Biodiversity research has traditionally focused on taxonomic diversity when investigating changes along elevational gradients,but other facets should be considered.For first time,we simultaneously assessed elevational trends in taxonomic,functional,and phylogenetic diversity of woody plants in Andean tropical montane forests and explored their underlying ecological and evolutionary causes.This investigation covered four transects(traversing ca.2200 m a.s.l.)encompassing 114 plots of 0.1 ha across a broad latitudinal range(ca.10).Using Hill numbers to quantify abundance-based diversity among 37,869 individuals we observed a consistent decrease in taxonomic,functional,and phylogenetic diversity as elevation increased,although the decrease was less pronounced for higher Hill orders.The exception was a slight increase in phylogenetic diversity when dominant species were over-weighted.The decrease in taxonomic and functional diversity might be attributed to an environmental filtering process towards highlands,where the increasingly harsher conditions exclude species and functional strategies.Besides,the differences in steepness decrease between Hill orders suggest that rare species disproportionately contribute to functional diversity.For phylogenetic diversity the shifting elevational trend between Hill orders indicates a greater than previously considered influence in central Andean highlands of tropical lowlands originated species with strong niche conservatism relative to distantly related temperate lineages.This could be explained by a decreasing presence and abundance of temperate,extratropical taxa towards the central Andes relative to northern or southern Andes,where they are more prevalent.Copyright©2024 Kunming Institute of Botany,Chinese Academy of Sciences.

A socioeconomic approach to the profile of microcredit holders from the Hispanic minority in the USA

The subject of this study is the microcredit market in the USA,more specifically in Florida.The justification for choosing this specific state is the massive presence of the Hispanic population.This will facilitate a generalization of the obtained results to the microcredit market in Latin American countries.Thus,the objective of this study is to analyze the profile of microcredit holders and their companies from socioeconomic and financial points of view.As our data also consider the degree of repayment of the microloans included in the sample,the clients’profile is related to the punctuality or default of their corresponding loan repayments using the methodology of multi-nomial logit regression.The variables used in this study refer to personal information concerning borrowers(gender,age,education level,and marital status),the economic situation of their respective companies(closeness to the lender,number of workers,and revenues),and the characteristics of granted loans(principal,term,and purpose).However,the results of the regression show that only two variables are significant at the 5%significance level:the borrower’s age,which has a positive effect on repay-ment punctuality,and the loan term,which exhibits a negative effect.The findings of this study have clear implications,as they can help lenders design suitable microloans adjusted to customer profiles.Finally,future research should include other demograph-ics and characteristics of affected companies.

Land-use change and windstorms legacies drove the recolonization dynamics of laurel forests in Tenerife, Canary islands

Laurel forests are quite relevant for biodiversity conservation and are among the island ecosystems most severely damaged by human activities.In the past,Canary laurel forests have been greatly altered by logging,livestock and agriculture.The remains of laurel forests are currently protected in the Canary Islands(Spain).However,we miss basic information needed for their restoration and adaptive management,such as tree longevity,growth potential and responsiveness to natural and anthropogenic disturbances.Using dendrochronological methods,we studied how forest dynamic is related to land-use change and windstorms in two well-preserved laurel forests on Tenerife Island.Wood cores were collected from over 80 trees per stand at three stands per forest.We used ring-width series to estimate tree ages and calculate annual basal area increments(BAI),cumulative diameter increases,and changes indicative of released and suppressed growth.Twelve tree species were found in all stands,with Laurus novocanariensis,Ilex canariensis and Morella faya being the most common species.Although some individuals were over 100 years old,61.8%-88.9% of the trees per stand established between 1940 and 1970,coinciding with a post-war period of land abandonment,rural exodus and the onset of a tourism economy.Some trees have shown growth rates larger than 1 cm diameter per year and most species have had increasing BAI trends over the past decades.Strong growth releases occurred after windstorms at both sites,but the effects of windstorms were site-dependent,with the 1958 storm affecting mainly the eastern tip of the island(Anaga massif)and the 1991 storm the western tip(Teno massif).Given the great ability of laurel forest trees to establish after land use cessation and to increase growth after local disturbances such as windstorms,passive restoration may be sufficient to regenerate this habitat in currently degraded areas.

磺酸多相催化剂用于二甲基亚砜中C_6-单糖脱水制5-羟甲基糠醛(英)

Sulfonic acid-functionalized heterogeneous catalysts have been evaluated in the catalytic dehydration of C(,monosaccharides into 5-hydroxymethylfurfural(HMF) using dimethyl sulfoxide(DMSO)as solvent.Sulfonic commercial resin Amberlyst-70 was the most active catalyst,which was ascribed to its higher concentration of sulfonic acid sites as compared with the other catalysts,and it gave 93 mol%yield of HMF from fructose in 1 h.With glucose as the starting material,which is a much more difficult reaction,the reaction conditions(time,temperature,and catalyst loading) were optimized for Amberlyst-70 by a response surface methodology,which gave a maximum HMF yield of 33 mol%at 147 °C with 23 wt%catalyst loading based on glucose and 24 h reaction time.DMSO promotes the dehydration of glucose into anhydroglucose,which acts as a reservoir of the substrate to facilitate the production of HMF by reducing side reactions.Catalyst reuse without a regeneration treatment showed a gradual but not very significant decay in catalytic activity.

High interpretable machine learning classifier for early glaucoma diagnosis

AIM:To develop a classifier for differentiating between healthy and early stage glaucoma eyes based on peripapillary retinal nerve fiber layer(RNFL)thicknesses measured with optical coherence tomography(OCT),using machine learning algorithms with a high interpretability.METHODS:Ninety patients with early glaucoma and 85 healthy eyes were included.Early glaucoma eyes showed a visual field(VF)defect with mean deviation>-6.00 d B and characteristic glaucomatous morphology.RNFL thickness in every quadrant,clock-hour and average thickness were used to feed machine learning algorithms.Cluster analysis was conducted to detect and exclude outliers.Tree gradient boosting algorithms were used to calculate the importance of parameters on the classifier and to check the relation between their values and its impact on the classifier.Parameters with the lowest importance were excluded and a weighted decision tree analysis was applied to obtain an interpretable classifier.Area under the ROC curve(AUC),accuracy and generalization ability of the model were estimated using cross validation techniques.RESULTS:Average and 7 clock-hour RNFL thicknesses were the parameters with the highest impor tance.Correlation between parameter values and impact on classification displayed a stepped pattern for average thickness.Decision tree model revealed that average thickness lower than 82μm was a high predictor for early glaucoma.Model scores had AUC of 0.953(95%CI:0.903-0998),with an accuracy of 89%.CONCLUSION:Gradient boosting methods provide accurate and highly interpretable classifiers to discriminate between early glaucoma and healthy eyes.Average and 7-hour RNFL thicknesses have the best discriminant power.

Effect of heat treatment on the mechanical and biocorrosion behaviour of two Mg-Zn-Ca alloys

The effect of heat treatment on the mechanical and biocorrosion behaviour of the Mg-1 wt.%Zn-1 wt.%Ca(ZX11)and Mg-3 wt.%Zn-0.4 wt.%Ca(ZX30)alloys was evaluated.For this purpose,three-point bending tests as well as electrochemical and immersion tests in Hank’s solution were performed on both alloys in four different thermal conditions:as-cast,solution-treated,peak-aged and over-aged.Microstructural examinations revealed that the as-cast ZX11 and ZX30 alloys exhibit a microstructure composed ofα-Mg grains separated by large Mg_(2)Ca and Ca_(2)Mg_(6)Zn_(3) particles and by large Ca_(2)Mg_(6)Zn_(3) particles,respectively.During solution treatment,the Ca_(2)Mg_(6)Zn_(3) precipitates at the grain boundaries(GBs)are fully dissolved in the ZX11 alloy,but mainly redistributed to form a more connected configuration in the ZX30 alloy,showing a poor age-hardening response.Consequently,after solution-treatment,galvanic corrosion and corrosion rate decreases in the former,but increases in the latter.The peak-aged condition displays the highest corrosion rate for both alloys,maybe due to an excessive number density of fine Ca_(2)Mg_(6)Zn_(3) particles acting as cathodic sites.However,the over-aged condition shows the lowest corrosion rate for the ZX11 alloy and a very similar one to that of the as-cast sample for the ZX30 alloy.The ZX11 alloy shows generally better biocorrosion behaviour than the ZX30 alloy to its lower content in the Ca_(2)Mg_(6)Zn_(3) phase and thus reduced galvanic corrosion.The Mg_(2)Ca phase present in the studied ZX11 alloy has been proved to exhibit an increased corrosion potential,which has been related to an observed enrichment with Zn.

A regionalized IO-model to value seasonal recreational ecosystem services in a mountain National Park in Spain

Recreational Ecosystem Services(RES)are among the most frequently evaluated ecosystem services.RES are seen as a major opportunity for sustainable development in areas of high ecological value resulting from the presence of emblematic species,habitats or scenery,often integrated in conservation areas,in particular in mountain areas affected by depopulation,rising environmental risks and poverty.Economically,the assessment of RES has been based on Contingent Valuation and Choice Experiments,methods with limitations related to their subjectivity.Alternatively,Input-Output(IO)models provide a very accurate and effective way of valuation of RES with regional information regarding interindustry transactions.Whilst data on nature tourist expenditure may be only available annually,tourism inflows have a strong seasonal behavior,which impacts the profitability of several local economic activities.In this paper,we firstly constructed a novel regionalized IO-model based on Cross-Industry Location Quotients using employment data and,secondly,based on Monte Carlo simulation,we estimated nature tourist expenditure monthly using data on nature tourism inflows.This method allowed for a more precise RES evaluation,estimating direct,indirect and induced monthly economic impacts of nature-based tourism.The method was applied to the Ordesa and Monte Perdido(OMP)National Park in the Spanish Pyrenees.To estimate the average tourist expenditure,we collected and analyzed spending on commerce,hospitality and restaurants,leisure,and transport of 385 visitors.Results suggest that using a regionalized IO model leads to a considerable reduction of over-estimation of the economic impact of tourist expenditure estimated by conventional methods.Taking into consideration the direct,indirect and induced effects of tourist expenditure in 2016-2018,the total annual output effect in the OMP National Park amounted to€208.8 million,while the total income effect amounted to€86.29 million.Also,a total of 2,429 jobs were created which indicates that for each thousand annual visitors to the National Park,3.8 jobs are created in the surrounding area.Overall,the proposed methodology can be easily applied to the remaining National Parks in Spain or other regions in the world,making it a valuable tool to estimate the value of RES in areas affects by strong seasonality,to set priorities and support regional policies for mountain sustainable development.

Hybrid Ensemble-Learning Approach for Renewable Energy Resources Evaluation in Algeria

In order to achieve a highly accurate estimation of solar energy resource potential,a novel hybrid ensemble-learning approach,hybridizing Advanced Squirrel-Search Optimization Algorithm(ASSOA)and support vector regression,is utilized to estimate the hourly tilted solar irradiation for selected arid regions in Algeria.Long-term measured meteorological data,including mean-air temperature,relative humidity,wind speed,alongside global horizontal irradiation and extra-terrestrial horizontal irradiance,were obtained for the two cities of Tamanrasset-and-Adrar for two years.Five computational algorithms were considered and analyzed for the suitability of estimation.Further two new algorithms,namely Average Ensemble and Ensemble using support vector regression were developed using the hybridization approach.The accuracy of the developed models was analyzed in terms of five statistical error metrics,as well as theWilcoxon rank-sum and ANOVA test.Among the previously selected algorithms,K Neighbors Regressor and support vector regression exhibited good performances.However,the newly proposed ensemble algorithms exhibited even better performance.The proposed model showed relative root mean square errors lower than 1.448%and correlation coefficients higher than 0.999.This was further verified by benchmarking the new ensemble against several popular swarm intelligence algorithms.It is concluded that the proposed algorithms are far superior to the commonly adopted ones.

The Taylor Rule and the Sandpile: The Taylor Contribution and Other Matters

The author of the Taylor Rule has provided new evidence about the application of the Sandpile model to his rule. The same findings of the Sandpile model are described in the Taylor paper in agreement with the conclusions of the Sandpile model. That is, that keeping interest rates too low for too long penalizes the economic recovery. On top of that the Sandpile also provides a metric for the severity of the crisis. The same law (Power Law) applies to the size and the duration of the crisis just modifying the order of the distribution paving thus a way for measuring the size of the crisis. According to the NBER data, the length is already determined for the US crisis, if the model holds on, we can also assess the severity.

Tropical forest canopies and their relationships with climate and disturbance： results from a global dataset of consistent field-based measurements

Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.

Relational coordination and healthcare management in lung cancer

In the current socio-economic scenario characterized by a growing shortage of resources and progressive budget constraints, the need to better coordinate processes in health institutions appears as a relevant aspect to ensure the future sustainability of system. In this sense, Relational Coordination(RC) provides a valuable opportunity for the reconfiguration of clinical guidelines concerning isolated single-level considerations. In this research the RC model has been applied to explain best results in the process of diagnosing and offering clinical treatments for lung cancer. Lung cancer presents the higher rates of tumor's mortality worldwide. Through unstructured and informal interviews with clinicians at both levels(Primary/Specialist Care), a diagnosis of the situation in relation to joint management of lung cancer is provided. Solutions of continuity in terms of coordination are explained due to the observation of lack of effective knowledge transfer between the two levels. It is this disconnection which justifies the introduction of a modified model of RC for the study and implementation of transfer relations between the knowledge holders, in order to structure consolidated and cooperative evidence-based models that lead to a substantial shortening in the response times with a marked outcomes improvement. To our knowledge, the application of this model to a Public Health problem bringing together both levels of care, hasn't been made till now.

Enhanced efficiency and stability in Sn-based perovskite solar cells by trimethylsilyl halide surface passivation

Lead free tin perovskite solar cells(PKSCs)are the most suitable alternative candidate for conventional lead perovskite solar cells.However,the efficiency and the stability are insufficient,mainly because of the poor film quality and numerous defects.Here we introduce an efficient strategy based on a simple trimethylsilyl halide surface passivation to increase the film quality and reduce the defect density.At the same time,a hydrophobic protective layer on the perovskite surface is formed,which enhanced the PKSCs’stability.The efficiency of the solar cell after the passivation was enhanced from 10.05%to 12.22%with the improved open-circuit voltage from 0.57 V to 0.70 V.In addition,after 92 days of storage in N_(2) filled glovebox,the modified T-PKSCs demonstrated high stability maintaining 80%of its initial efficiency.This work provides a simple and widely used strategy to optimize the surface/interface optoelectronic properties of perovskites for giving more efficient and stable solar cells and other optoelectronic devices.

Security Threats to Business Information Systems Using NFC Read/Write Mode

Radio Frequency IDentification(RFID)and related technologies such as Near Field Communication(NFC)are becoming essential in industrial contexts thanks to their ability to perform contactless data exchange,either device-to-device or tag-to-device.One of the three main operation modes of NFC,called read/write mode,makes use of the latter type of interaction.It is extensively used in business information systems that make use of NFC tags to provide the end-user with augmented information in one of several available NFC data exchange formats,such as plain text,simple URLs or enriched URLs.Using a wide variety of physical form factors,NFC-compatible tags(wireless transponders)are currently available in many locations with applications going from smart posters,contactless tokens,tap-and-go payments or transport ticketing to automated device configuration,patient identification at hospitals or inventory management within supply chains.Most of these applications handle sensitive processes or data.This paper proposes a complete security threat model for the read/write operation mode of NFC used in Next Generation Industrial IoT(Nx-IIoT)contexts.This model,based on a wellknown methodology,STRIDE,allows developers and users to identify NFC applications vulnerabilities or weaknesses,analyze potential threats,propose risk management strategies,and design mitigation mechanisms to mention only some significant examples.

Diversity of Saxicolous Lichens along an Aridity Gradient in Central México

Lichens are symbiotic organisms that comprise a fungus and a photosynthetic partner wich are recognized as a good indicator of climate change.However,our understanding of how aridity affects the diversity of saxicolous lichens in drylands is still limited.To evaluate the relationship between saxicolous lichen diversity and aridity in a central México dryland,a geographical transect was established of 100 km to build an aridity gradient in the semiarid zone of the State of Querétaro,Mexico,comprising ten sampling sites with a 10 km separation.Species richness,abundance and diversity of soil lichen species were recorded using two sampling methods:the quadrat-intercept and the line-intercept method,to compare their performance in assessing soil lichen diversity in drylands.The number of species and Shannon diversity of saxicolous lichens were higher at intermediate values of the aridity index(AI=0.10-0.34).Quadrat intercept and point intercept methods gave quite similar results,which means that the selected method does not influence the results in a significant way.This study confirms the role of saxicolous lichens as climate change indicators and reveals the importance of the sampling method selection in the evaluation of different parameters of soil lichen diversity in drylands.

Six forests in one:Tree species diversity in the Bosque Protector Chongón Colonche,a lowland mountain range in coastal Ecuadorian

Tropical mountain ranges shape the structure of tree communities and promote highly diverse natural habitats.The“Bosque Protector Chong on-Colonche”(BPCC),an 86,000-ha mountain formation situated on the coast of Ecuador,is biogeographically important for the region by connecting floristic elements of the wet Choco and the dry Tumbesian forests.Our understanding of the factors that model tree and palm diversity and distribution in this mountain range are limited.We measured and identified all trees and palms(DBH≥10 cm)in 289 plots of0.2 ha,distributed throughout BPCC.We used generalized linear models to explain the relationship between forest diversity and structure and climatic variables(temperature,rain,aridity),and altitude.We then used cluster and non-metric multidimensional scale(NMDS)analyses to search for distinct forest communities within the BPCC.Variance partition(varpart)was used to determine which predictor variables best explained these distinct forest communities.A species indicator analysis identified the species most likely to define these distinct forest communities.Finally,we carried out a niche modeling approach to identify the potential distribution of these forest communities within BPCC.In total,we identified 220 tree and palm species in our survey.The average number of species per plot was 17.8±5.8,ranging from 3 to 40 species.Classification methods sorted the 289study plots into six different forest communities,three communities in the dry forest and three in the semi-humid Garúa forest.Precipitation and temperature,but not altitude or aridity,explained floristic composition.These results emphasize the high but little cataloged diversity in the lowland mountain rainforests of coastal Ecuador.

The Emergence of New Business and Operating Models under the Industrial Digital Paradigm.Industrial Internet of Things,Platforms,and Artificial Intelligence/Machine Learning

This paper pretends to approach and analyse opportunities and risks that arise under the industrial digital paradigm.Known by different names like Industry 4.0,Smart Manufacturing,or Production 4.0,among other terms digitalization in industry is advancing at a tremendous speed,and is pushing established firms to change and adopt new tools.Besides,it opens opportunities to technological startups to deliver new products and services to the industrial market.As an example of opportunities in operating models,it is clear that digitalization under the model Industry 4.0 and the advantages of Industrial Internet of Things(IIoT),allows faster response to customer demands,increases flexibility allowing the adaptability to manufacturing processes,and provides a tremendous amount of tools for quality improvement in the processes,among other advantages.This article addresses the data driven organization as digitalization evolves and the progress of Artificial Intelligence(AI)and Machine Learning(ML)solutions for industry.

Risk Factors and Gender Differences for Depression in Chilean Older Adults:A Cross-Sectional Analysis from the National Health Survey 2016–2017

Depressive disorders are recognized as one of the most common mental health conditions across different age groups.However,the risk factors associated with depression among older people from low-and middle-income countries remains unclear.This study aims to identify socio-demographic,health and psychosocial-related factors associated with depression in Chilean older adults.A cross-sectional study was carried out in a representative sample of 1,765 adults aged≥60 years participants from the Chilean National Health Survey 2016–2017.Depres-sion was assessed with the Composite International Diagnostic Interview(CIDI-SF).Associations between the exposure variables and depression were investigated using Poisson regression analyses.The mainfindings indi-cated that women showed higher likelihood of depression than men(Prevalence Ratio(PR)=2.6[95%CI:1.40;4.89]).An increased likelihood of depression was found in older adults with chronic pain,multimorbidity(≥2 diseases),previous diagnose of depression,high perception of stress,financial stress,and difficulties for social par-ticipation.In women,higher likelihood of depression was found for those with the frailty phenotype(PR:8.53[95%CI:1.68;43.32]),rheumatoid arthritis(PR:2.41[95%CI:1.34;4.34]),insomnia(PR:2.99[95%CI:1.74;5.12])and low self-rated well-being(PR:4.94[95%CI:2.26;10.79]).Men who were divorced(PR:7.10[95%CI:1.44;34.90])or widowed(PR:10.83[95%CI:3.71;31.58]),obese(PR:5.08[95%CI:1.48;17.42])and who had asthma(PR:7.60[95%CI:2.31;24.99])were associated with higher odds of depression.The currentfindings may have clinical implications for the early identification of older adults more susceptible to depression and also suggest the need to implement cultural and age-sensitive strategies to promote mental health in late life.

Acceptance of living liver donation among medical students: A multicenter stratified study from Spain

AIM: To analyze the attitude of Spanish medical students toward living liver donation(LLD) and to establish which factors have an influence on this attitude.METHODS: Study type: A sociological, interdisciplinary, multicenter and observational study. Study population: Medical students enrolled in Spain(n = 34000) in the university academic year 2010-2011. Sample size: A sample of 9598 students stratified by geographical area and academic year. Instrument used to measure attitude: A validated questionnaire(PCID-DVH RIOS) was self-administered and completed anonymously. Data collection procedure: Randomly selected medical schools. The questionnaire was applied to each academic year at compulsory sessions. Statistical analysis: Student′s t test, χ2 test and logistic regression analysis.RESULTS: The completion rate was 95.7%(n = 9275). 89%(n = 8258) were in favor of related LLD, and 32%(n = 2937) supported unrelated LLD. The following variables were associated with having a more favorable attitude:(1) age(P = 0.008);(2) sex(P < 0.001);(3) academic year(P < 0.001);(4) geographical area(P = 0.013);(5) believing in the possibility of needing a transplant oneself in the future(P < 0.001);(6) attitude toward deceased donation(P < 0.001);(7) attitude toward living kidney donation(P < 0.001);(8) acceptance of a donated liver segment from a family member if one were needed(P < 0.001);(9) having discussed the subject with one's family(P < 0.001) and friends(P < 0.001);(10) a partner's opinion about the subject(P < 0.001);(11) carrying out activities of an altruistic nature; and(12) fear of the possible mutilation of the body after donation(P < 0.001).CONCLUSION: Spanish medical students have a favorable attitude toward LLD.