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    Templated tube growth about a reactive gas plume: The pharaoh's serpent reaction, thermodecomposition of mercury thiocyanate in air
    (ChemSystemsChem, 2026) Pimentel Guerra, Carlos; Testón Martínez, Sergio; Gutiérrez Ariza, Carlos; Sainz Díaz, Ignacio; Cartwright, Julyan H. E.
    The pharaoh's serpent reaction, the thermodecomposition of mercury thiocyanate in air, is a classic chemical demonstration. We analyse and characterize the reaction products, composed of two different phases, graphitic carbon nitride, mathematical equationmathematical equation, and metacinnabar, HgS. We show that two growth modes are involved in forming the sinuous solid product; the more common one, jack-up growth, forms a solid cylinder from the base up. This is accompanied by a rarer second mode, chimney growth, in which fluid mechanics plays a fundamental role. In this second growth mode, reagents are transported in gaseous form in a reactive plume to be precipitated remotely on the growing rim of a tube templated around the plume. Such templated tube growth, while common in a liquid environment, for example, in the chemical-garden reaction, has not been reported in a gaseous medium.
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    A kinematic model of the Scotia plate (SW Atlantic Ocean)
    (Journal of South American earth sciences, 2003) Giner Robles, Jorge Luis; González Casado, J.M.; Gumiel, Pablo; Martín Velázquez, Silvia; García Cuevas, C.
    The focal mechanisms located around the Scotia plate were examined by fault population analysis to calculate both the trends of the maximum horizontal shortening on the plate and the orientations of its associated faults. The results show that both the northern and southern boundaries of the Scotia plate (the north and south Scotia ridges) are currently undergoing left-lateral movement. This movement induces a left-lateral shear couple in the whole plate, with a maximum horizontal NE–SW shortening direction. The established fault orientations and fault classes closely match the predicted structural pattern of a theoretical shear couple that includes the entire Scotia plate. The stress trajectories deduced from finite element modeling also agree with the proposed left-lateral shear couple model; the calculated stress trajectories are characterized by a homogeneous NE–SW compression direction over the whole Scotia plate. This shear model also explains the slip of recent tectonic structures found at the boundaries of the Scotia plate and suggests the possibility of reactivation of its former tectonic structures.
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    Moulting behaviors in oryctocephalid trilobites reveal ontogenetic shifts in ecdysial strategies
    (Palaeogeography, Palaeoclimatology, Palaeoecology, 2026) Wang, Yifan; Esteve Serrano, Jorge Vicente; Wang, Dezhi; Ren, Guangying; Zhang, Hui; Luo, Xiuchun; Yang, Xinglian
    Similar to other arthropods, trilobite underwent ecdysis as a periodic stage, and this life history strategy had a profound effect on their ontogeny and morphological evolution. Previous paleontological studies of moulting behavior in trilobites are based on few exuviae within later meraspides and holaspid phases, and also too little is known about ontogenetic mouting behavior in trilobites. Here, we investigate abundant exuviae exhibiting relatively complete ontogenetic sequences of Arthricocephalus chauveaui, Arthricocephalites xinzhaiheensis, Duyunaspis duyunensis and Changaspis elongata from the Cambrian Stage 4 Balang Formation. The results indicate two clear trends of ontogenetic moulting behavior in oryctocephalid trilobites during development. A. chauveaui utilized a single Somersault moulting pattern, which deals with opening the cephalic sutures (facial and rostral sutures), with lower cephalic unit (LCU) somersaulting anteriorly and lying beneath the trunk in moult assemblages. However, a gradual transition of moulting behavior during the development, from Somersault to Henningsmoen's moulting pattern, i.e., from inverting the LCU to disarticulated cranidium, is confirmed in Ar. xinzhaiheensis, D. duyunensis and C. elongata. This shift during development might reflect an evolutionary experiment with different moulting modes throughout development, a significant transition with macroevolutionary implications. The moulting mode may be canalized by structures that develop or change with growth, meaning that the change in strategy is not optional, but rather a consequence of morphological constraints and developmental pathway.
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    Late Pleistocene temperature patterns in the Western Palearctic: insights from rodent associations compared with general circulation models
    (Climate of the Past, 2025) Royer, Aurélien; Crétat, Julien; Laffont, Rémi; Gamboa Jurado-Centurión, Sara; Luna, Belén; Menéndez González, Iris; Pohl, Benjamin; Montuire, Sophie; Hernández Fernández, Manuel
    Since rodent fossils are preserved in many low- and high-latitude archaeological and paleontological sites from a wide variety of environments, their associations are a commonly useful proxy for inferring past local climate and environmental conditions. Such a frequent and widespread geographic distribution can help us to better understand past climate evolution by providing access to high spatiotemporal resolution at large geographical scales. The aim of this paper is to develop an approach to generate continental-scale temperature maps based on rodent associations and to assess their reliability compared to state-of-the-art general circulation models (GCMs). We used the Bioclimatic Analysis, based on fossil and modern rodent associations, to infer climate zone distribution and local temperatures (mean annual temperature, mean temperature of the warmest month and mean temperature of the coldest month), at the Western Palearctic (Europe, Middle East and North Africa) for six different periods: the Last Glacial Maximum (LGM), Heinrich Stadial, Bølling, Allerød, Younger Dryas and present-day conditions. The Bioclimatic Analysis is combined with a spatial generalized linear mixed model to interpolate these surface temperatures across the Western Palearctic. We show that the spatial patterns in mean annual temperature and mean temperature of the warmest and coldest months are very similar between our interpolations and GCMs for both present-day and LGM conditions, but the rodent-based approach provides slightly cooler LGM estimations in western Europe and warmer ones in eastern Europe. Throughout the Late Glacial oscillations, the rodent-based model infers globally small variations in mean annual temperature and mean temperature of the warmest months and slightly larger changes in mean temperature of the coldest months. Nonetheless, some events show weak but significant regional variations depending of the events and the climate variable. For instance, the most important shifts in mean annual temperature between the Allerød and Younger Dryas are observed in northwestern regions. Northeastern regions, on the other hand, experienced relatively stable mean annual temperature, although they did experience considerable warming of the warmest month and cooling of the coldest month. Minor discrepancies appear between GCMs and the rodent-based model, the latter showing colder temperature in northwestern Europe and hence a differential west–east gradient in ice-sheet influence. Our results demonstrate that rodent associations are robust proxies for reconstructing and regionalizing past temperatures at broad scales, offering a readily reproducible approach to be reimplemented in future studies incorporating new rodent data.
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    Experimental study on marly clay stabilization under short-term conditions using volcanic ash and reactivity-controlled lime as activator
    (Infrastructures, 2025) Ponce, Roberto; Melentijevic Devetakovic, Svetlana; Montero, Natalia; López De Andrés, María Sol
    Expansive soils undergo significant volume changes with moisture fluctuations, posing persistent challenges for infrastructure due to heave, settlement, and loss of bearing capacity. Stabilization is a common mitigation strategy, though traditional binders, such as cement and lime, are associated with high energy consumption and considerable CO2 emissions. In this context, identifying low-carbon alternatives is essential. This study evaluates the short-term behavior of expansive marly clays from southern Spain stabilized with volcanic ash generated during the 2021 Tajogaite eruption (La Palma, Canary Islands, Spain). Volcanic ash was incorporated in different proportions to assess its performance as a natural pozzolan, while natural hydrated lime was used both as a direct stabilizer and as an activator to enhance ash reactivity. A key methodological contribution of this research is the monitoring of lime reactivity throughout storage, using XRD and TGA to quantify portlandite loss and partial carbonation before mixing—an aspect seldom addressed in stabilization studies. The experimental program included chemical and mineralogical characterization, compaction, Atterberg limits, free swelling, unconfined compressive strength, and direct shear tests on natural and stabilized mixtures. The results show that volcanic ash, particularly when lime-activated, substantially improves volumetric stability. Free swelling decreased from 11.9% in the natural soil to values as low as 1.7%, while dry density increased and plasticity decreased. Strength gains were modest under short-term conditions, consistent with the limited time for pozzolanic reactions to develop. The combined use of volcanic ash and lime reduced the lime demand required to achieve equivalent volumetric control, offering an eco-efficient and technically viable alternative for stabilizing expansive marly clays.
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    Portable X-ray fluorescence (pXRF) application to the determination of major and trace elements in large soil datasets for geochemical background assessment
    (Journal of Geochemical Exploration, 2026) Martínez Del Pozo, Iker; Gómez Pachón, Mónica Celina; Ferri Moreno, Inmaculada; García Lorenzo, María de la Luz; Lorenzo Álvarez, Saturnino; Barquero Peralbo, Jose Ignacio; Arroyo Rey, Xabier; Higueras Higueras, Pablo; Esbrí Víctor, José María
    Regional soil geochemical surveys are essential for land-use planning and human health. However, projects involving large sample sets characterised using traditional laboratory techniques are costly, time-consuming and require a large number of reagents. Therefore, the use of portable X-ray fluorescence (pXRF) with an optimised measurement time and methodology, along with minimal sample preparation, allows for fast and effective measurements. In this study, using Soil-Fundamental Parameters (S-FP) method, a measurement time of 45 s and low sample preparation yielded acceptable results for K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Zr, and Pb, which were monitored with benchtop XRF equipment. The application of this methodology in Cuenca province, Spain, and the comparison with different European and national programmes provides consistency in the results, despite using different analytical techniques. It was observed that a systematic and regular sampling strategy avoids geochemical gaps, increasing the representativeness of the soil parent material in the samples. Distinct geochemical patterns have been identified, with a major group comprising Ti, Mn and Fe, and trace elements such as Cr, Ni, Cu, Zn, As, Rb, Sr, Zr and Pb, while K, Ca and Sr display individual distribution trends. Therefore, this study provides a rapid and economical way to characterise soil geochemistry in large areas and to establish background and reference levels over extensive regions.
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    Tratamiento poscosecha con aceite esencial de tomillo en uva ‘Crimson’ Aceites esenciales como alternativa de conservación poscosecha
    (Actual Poscosecha. Avances en Ciencia y Tecnología 2025 Producción hortícola y poscosecha, 2025) Fernández-León, Ana María; Laranjo, Marta; Agulheiro-Santos, Ana Cristina; Elias, Miguel; Fernández León, María Fernanda
    Para prolongar la vida útil de la fruta después de recolección, es preciso la aplicación de tratamientos poscosecha que consisten en el uso de técnicas de barrera donde se combina temperatura y humedad, además en algunas ocasiones es necesario también el uso de conservantes químicos, con el inconveniente que se ha asociado al uso de estos productos, con intoxicaciones, alergias y otras enfermedades. Por esta causa, y porque los consumidores cada vez demandan productos más naturales, se deben buscar alternativas de conservación. Las plantas aromáticas han sido usadas como conservantes desde hace mucho tiempo, pudiendo extraerse de ellas aceites esenciales, que tienen efectos sobre el crecimiento microbiano, que es la principal causa de deterioro de los alimentos. El objetivo de este trabajo fue el estudio de la acción del aceite esencial de tomillo sobre la calidad fisicoquímica, sensorial y microbiológica de la uva de mesa ‘Crimson’. Se realizaron dos tratamientos: control y tomillo, conservándose en refrigeración (2 °C ± 1 °C y 95% HR) y realizándose seguimientos a los 7, 14, 21, 28 y 35 días. En cada fecha se evaluó: la pérdida de peso, la deshidratación del raspón, la firmeza, la acidez, los sólidos solubles totales, y la evolución microbiológica (mesófilos aerobios, psicrotrofos, mohos y levaduras) así como la calidad sensorial. El tratamiento con aceite esencial de tomillo mostró buenos resultados, debido a que presentó: menores pérdidas de firmeza y pérdidas de peso, mantuvo el color verde del raspón y el recuento microbiológico fue más bajo que en las muestras control, además de ser valorados positivamente sensorialmente.
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    Characterizing dry and humid heatwaves in Southern South America: regional trends and large-scale climate drivers
    (Climate Dynamics, 2026) López Ramírez, Agustina; Barrucand, Mariana; Collazo Inglesini, Soledad Maribel
    This study characterizes the spatiotemporal variability of heatwaves occurring under dry and humid conditions during the warm season (October–March) in southern South America (SSA) between 1979 and 2018. Using daily maximum temperature and precipitation data from 132 meteorological stations, we identified compound extremes based on the co-occurrence (simultaneous or sequential) of heatwaves with anomalously dry or wet conditions, defined by the Standardized Precipitation Index. Four types of compound events were analyzed: simultaneous and sequential dry heatwaves (SIDH, SEDH), and simultaneous and sequential humid heatwaves (SIHH, SEHH). SIDH and SEDH were the most common compound events, particularly in northeastern and central Argentina, while humid events (SIHH and SEHH) were generally less frequent, especially SIHH. Changes in frequency, duration, intensity, and spatial extent of compound heatwaves were examined by comparing two subperiods (1979–1998 and 1999–2018). Our findings show an increase in the frequency and spatial extension of dry events (SIDH and SEDH) and SEHH in recent decades. We also investigated the influence of large-scale climate drivers—El Niño–Southern Oscillation, Pacific Decadal Oscillation (PDO), Indian Ocean Dipole (IOD), and Southern Annular Mode (SAM)—and their combined phases on compound heatwave occurrence. In particular, the concurrent occurrence of La Niña, negative PDO, negative IOD, and positive SAM phases was associated with an increased occurrence of dry compound heatwaves and a reduction in humid ones. These findings highlight the importance of understanding compound heatwaves, especially in regions like SSA where land–atmosphere feedbacks and climate variability strongly influence extremes.
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    Unraveling the kinematics of IZw18: a detailed study of ionized gas with MEGARA/GTC
    (Astronomy & Astrophysics, 2024) Arroyo Polonio, A.; Kehrig, C.; Iglesias-Páramo, J.; Vílchez, J. M.; Pérez-Montero, E.; Duarte Puertas, S.; Gallego Maestro, Jesús; Reverte, D.; Cabrera Lavers, A.
    This study offers an in-depth analysis of the kinematic behavior of ionized gas in IZw18, a galaxy notable for its extremely low metallicity and close proximity, utilizing data from MEGARA/GTC. We explored the structure and dynamics of the galaxy through Hα line profiles, applying single and double Gaussian component fittings to create detailed maps of the luminosity, velocity, and velocity dispersion in the main body (MB) and halo regions. Additionally, we retrieved integrated spectra from various galactic regions to achieve a higher signal-to-noise ratio. In the MB, a rotational pattern is evident, yet a secondary, more complex kinematic pattern emerges from the double-component fitting, which is further enriched by the identification of a very broad component. Distinguished by a full width at half maximum of nearly 2000 km s^(−1) and a wide spatial extension, this component suggests a high-energy outflow and points toward large-scale, nonlocalized sources of high kinetic energy. Additionally, the observed significant velocity differences between the narrow and very broad components imply that these gases may occupy distinct spatial regions. This is potentially explained by high-density gas near the origin of the kinematic input, acting as a “wall” that reflects back the momentum of the gas. Regarding the halos, while the NE halo exhibits a tranquil state with low velocity dispersions, the SW halo presents higher velocities and more complex kinematics, indicative of diverse dynamic interactions. The identification of the very broad component across the MB and the high kinematic complexity in all regions of the galaxy points toward a scenario of widespread and subtle turbulent motion. This nuanced understanding of the kinematic behavior in IZw18, including the interplay of different gas components and the influence of internal structures, enhances our comprehension of the dynamics in blue compact dwarf galaxies. It may provide critical insights into early galaxy formation and the intricate kinematics characteristic of such environments.
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    The role of nest-box density and placementon occupation rates and breeding performance: a case study with Eurasian Blue Tits
    (Ornis Fennica, 2017) Serrano Davies, Eva; Barrientos Yuste, Rafael; Sanz, Juan José
    The use of nest-boxes to study bird breeding biology, as well their use as a management tool, is widespread. The exact placement of nest-boxes may affect individual preference for these breeding sites; however the influence of determinant factors (e.g., nest-box density) in occupation rates or breeding parameters has not been sufficiently covered. Here, we used the Eurasian Blue Tit as a model species to determine factors influencing nestbox selection in a transformed habitat: a pine plantation. Our study design consisted of 100 nest-boxes arranged at different heights (positioned "high" at 3.0-5.0 m, or positioned "low"at 1.5-2.0m), andwith different degrees of clustering (clustered in groups of 6, or isolated by at least 80mfrom the nearest nest-box).We calculated the potential territorial area for each nest-box and the distance to the nearest neighbour.We investigated the influence of nest-box position and breeding pair density on occupation rate and breeding success, controlling for habitat structure. Eurasian Blue Tits preferentially selected nestboxes located high on the tree and with fewest neighbours. Laying date was earlier in higher nest-boxes and in those with fewer neighbours and at a greater distance from the nearest neighbour. The number of nestlings was positively related to shrub cover andmedium tree height. Fledgling mass was higher when distance to the nearest neighbour was greater and fledgling tarsus length was positively related to oak-species abundance. Our results suggest that disentangling the important factors for nest-box placement and spatial dispersion in the landscape is important to adapt to species-specific requirements in each given habitat.
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    Baltasar Gracián y las imágenes matemáticas
    (Edad de Oro, 2025) Blanco Gómez, Emilio Francisco
    RESUMEN: Estudio detallado de la imaginería matemática en la prosa tratadística de Baltasar Gracián, cuyo uso se incrementa progresivamente desde "El Héroe" hasta el "Oráculo manual". En la primera parte se evidencia del interés del jesuita por este tipo de expresiones figuradas aplicadas al comportamiento ético. En la segunda se señala la importancia de la matemática en el mundo jesuítico. En la tercera se ofrece un análisis pormenorizado de la expresión matemática aplicada al gobierno ético.
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    Gravity from equilibrium thermodynamics of stretched light cones
    (Physical Review D, 2025) Alonso-Serrano, Ana; Garay Elizondo, Luis Javier; Liška, Marek; López Pineros, Celia
    This work digs into the connection between gravity and thermodynamics of stretched light cones (SLC). They are associated with uniformly accelerating observers, who endow the SLC with a physical notion of temperature via the Unruh effect. We compute the expansion, shear, and vorticity of the SLC to fully study its dynamics and account for the possibility of previously predicted nonequilibrium entropy production. For consistency, we prove the equivalence of the two different geometrical methods available for studying the SLCs’ properties. Then, we apply the energy balance and use Clausius’ relation to relate the geometrical properties of the SLC with energy fluxes crossing its surface, showing that it encodes the equations governing the gravitational dynamics. We show here how this analysis can be fully carried in terms of equilibrium thermodynamics due to the vanishing of shear, and how one can identify a work term related to the acceleration of the observer.
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    Aurora como proyecto educativo
    (Estudios Nietzsche. Revista de la Sociedad Española de estudios sobre Friedrich Nietzsche (SEDEN), 2021) Rodríguez González, Mariano Luis
    Las reflexiones educacionales de Aurora se compaginan bien con la general filosofía nietzscheana de la educación, al liberar al individuo de la moralidad de la costumbre, porque solo así será capaz de llegar a ser el que es. Demandará Nietzsche una educación que enseñe a soportar la soledad como camino hasta uno mismo y la propia creatividad. Se subraya, también, su crítica de las instituciones educativas de la época, para acabar tratando el problema filosófico central de la educación, el planteado por el nuevo sujeto pulsional nietzscheano.
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    Bioelectrical Impedance Analysis as a Non-Invasive Approach to Estimate In Vivo Body Composition in Rabbit Does Across Physiological Stages
    (Animals, 2025) Nicodemus, Nuria; Pereda, Nelly; Fuentespila, Joaquín; Lorenzo González, Pedro Luis; Rebollar, Pilar G.
    The assessment of temporal changes in the body chemical composition of reproductive does across successive reproductive cycles is crucial for research, technical, and commercial applications, as it contributes to optimizing reproductive performance and lifespan. Furthermore, the implementation of non-invasive techniques is desirable to ensure animal welfare. The present study demonstrates that bioelectrical impedance analysis (BIA) provides an accurate and non-invasive approach for evaluating the dynamic changes in the chemical composition of female rabbits throughout their productive lifespan, eliminating the need for slaughter.
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    In vitro embryo production in the Iberian lynx (Lynx pardinus) using oocytes recovered post-mortem and cryopreserved spermatozoa
    (Theriogenology Wild, 2026) Priego González, Andrea; Munoz-Maceda, Ana; González, Raquel; Rielo, Juan Antonio; Gañán, Natalia; Sánchez Rodríguez, Ana; Villar-Moya, Pilar; Cantos Rubert, Ana; Sánchez Calabuig, María Jesús; Roldan, Eduardo R.S.
    The Iberian lynx (Lynx pardinus), once considered the most endangered felid in the world, has become a remarkable example of conservation success thanks to intensive ex situ and in situ management efforts. However, the long-term viability of the species remains under threat. The implementation of assisted reproductive technologies (ARTs) would contribute to ensure the species viability, but the use of ARTs is limited in this species and there are still important gaps in the knowledge of its physiology. Here, we report the first in vitro fertilization (IVF) and early embryo development in the Iberian lynx using oocytes retrieved post-mortem and cryopreserved spermatozoa. Oocytes from six females were subjected to in vitro maturation using two sets of conditions. In the first series, oocytes incubated in vitro for 24 h, exhibited a very low proportion (0–37 %) reaching metaphase II (MII). Attempted IVF with cryopreserved spermatozoa resulted in no fertilization. In a second series, oocytes were incubated in vitro for 28 h; grade I-II oocytes exhibited 40 % maturation rate (MII), whereas grade III oocytes showed 28 % maturation rate. Matured oocytes from one female were co-incubated with cryopreserved sperm for 18 h resulting in cleavage rates of 39.3 % (grade I–II) and 7.1 % (grade III) and the opportunity to vitrify one blastocyst and six morulae. These results demonstrate the feasibility of using ARTs in this species, validating domestic cat protocols for Iberian lynx gametes, and providing a foundation for further refinement of IVF protocols, embryo cryopreservation, and ultimately, embryo transfer strategies for use in conservation programs.
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    Colorectal cancer screening with fecal occult blood testing
    (Revista Española de Enfermedades Digestivas, 2008) Díaz Tasende, José Benjamín; Marín Gabriel, José Carlos
    Colorectal cancer (CRC) is a public health issue worldwide. Both in Europe and in most developed countries colorectal cancer represents the second most common neoplasm in both genders, and the second most common cause of cancer-related death. Most deaths from colorectal cancer may be prevented, and there is solid consensus on the need for CRC screening programs in the mid-risk population. The most efficient strategy remains to be defined, regarding which the development of an easily administered, highly sensitive, specific test bringing about an improvement of current adherence is essential. Increased awareness among the population regarding the benefits of early diagnosis, and straightforward access to healthcare resources are important issues.
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    Alzheimer’s Disease and Empathic Abilities: The Proposed Role of the Cingulate Cortex
    (Journal of Alzheimer’s Disease Reports, 2021) Avila Villanueva, Marina; Gomez Ramırez, Jaime; Avila, Jesús; Fernández Blázquez, Miguel Ángel
    In recent years there has been increasing interest in examining the role of empathic abilities in Alzheimer’s disease (AD). Empathy, the ability to understand and share another person’s feelings, implies the existence of emotional and cognitive processes and is a pivotal aspect for success in social interactions. In turn, self-empathy is oriented to one’s thoughts and feelings. Decline of empathy and self-empathy can occur during the AD continuum and can be linked to different neuroanatomical pathways in which the cingulate cortex may play a crucial role. Here, we will summarize the involvement of empathic abilities through the AD continuum and further discuss the potential neurocognitive mechanisms that contribute to decline of empathy and self-empathy in AD.
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    How to prevent and/or revert Alzheimer’s disease continuum during preclinical phases
    (Journal of Alzheimer’s Disease Reports, 2023) Avila Villanueva, Marina; Marcos Dolado, Alberto; Fernández Blázquez, Miguel Ángel
    The development of Alzheimer’s disease (AD) follows three consecutive phases: namely preclinical, prodromal or mild cognitive impairment (MCI), and dementia. In addition, the preclinical phase can be divided into subphases related to the presence of biomarkers that appear at different points before the onset of MCI. Indeed, an early risk factor could promote the appearance of additional ones through a continuum. The presence of various risk factors may trigger specific biomarkers. In this review, we comment on how modifiable risk factors for AD may be reverted, thus correlating with a possible decrease in the specific biomarkers for the disease. Finally, we discuss the development of a suitable AD prevention strategy by targeting modifiable risk factors, thereby increasing the level of “precision medicine” in healthcare systems worldwide.
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    Skeletal maturation determined by cervical vertebrae development
    (European Journal Orthodontics, 2002) San Román Calvar, Paloma; Palma Fernández, Juan Carlos; Oteo Calatayud, María Dolores; Nevado Rodríguez, María Esther
    The aim of this study was to determine the validity of cervical vertebrae radiographic assessment to predict skeletal maturation. Left hand-wrist and lateral cephalometric radiographs of 958 Spanish children from 5 to 18 years of age were measured. On the left hand-wrist radiographs the classification of Grave and Brown was used to assess skeletal maturation. Cervical vertebrae maturation was evaluated with lateral cephalometric radiographs using the stages described by Lamparski and by Hassel and Farman. A new method to evaluate the cervical maturation by studying the changes in the concavity of the lower border, height, and shape of the vertebral body was created. Correlation coefficients were calculated to establish the relationship between skeletal maturation values obtained by the three classifications of vertebral and skeletal maturation measured at the wrist. All correlation values obtained were statistically significant (P < 0.001). The results suggest that this new method to determine skeletal maturation is very reliable. A simple method based on morphological characteristics of the cervical vertebral bodies to evaluate the maturation stage has been designed. In the population investigated, this method is as accurate as the Hassel and Farman classification and superior to the Lamparski classification. The morphological vertebral parameter best able to estimate the maturation is the concavity of the lower border of the body.