Seed Weight and Trade-Offs: An Experiment in False Rhodes Grasses under Different Aridity Conditions.

The false Rhodes grasses [Leptochloa crinita (Lag.) P.M. Peterson and N.W. Snow and Leptochloa pluriflora (E. Fourn.) P.M. Peterson and N.W. Snow] are considered valuable native forage resources for arid and semiarid rangelands in Argentina and the United States. Effectively using plant materials as forage under aridity conditions requires understanding their resource allocation under those conditions. In the present study, plant functional traits were evaluated in six populations of each false Rhodes grass species from different geographic origin in a humid and an arid region. The evaluation was focused on seed weight, due to the key role of this trait in plant survival. The implication of seed weight in germination under osmotic stress and trade-off relationships between functional traits were also analysed. A fixed ontogenetic variation was found in both species, since populations maintained a stable seed weight across environments. The tolerance to osmotic stress at germination stage was more related to seed weight than to population origin or maternal environment of seeds; heavier-seeded populations produced heavier seedlings instead of a higher number of germinated seeds or higher germination rates. Some traits varied between environments but other traits exhibited a fixed response. Variation patterns among populations were similar within environments and in some cases even for populations from the same geographic origin, revealing a fixed ontogenetic variation; this phenomenon was clearer in L. crinita than in L. pluriflora. Moreover, several different trade-off strategies were detected in both species. These results reinforce the knowledge about the key role of seed weight in survival and performance of seedlings at initial growth stages under arid conditions; however, at advanced stages, other traits would have an important function in growth and development of false Rhodes grasses.

Drivers of seedling establishment success in dryland restoration efforts.

Restoration of degraded drylands is urgently needed to mitigate climate change, reverse desertification and secure livelihoods for the two billion people who live in these areas. Bold global targets have been set for dryland restoration to restore millions of hectares of degraded land. These targets have been questioned as overly ambitious, but without a global evaluation of successes and failures it is impossible to gauge feasibility. Here we examine restoration seeding outcomes across 174 sites on six continents, encompassing 594,065 observations of 671 plant species. Our findings suggest reasons for optimism. Seeding had a positive impact on species presence: in almost a third of all treatments, 100% of species seeded were growing at first monitoring. However, dryland restoration is risky: 17% of projects failed, with no establishment of any seeded species, and consistent declines were found in seeded species as projects matured. Across projects, higher seeding rates and larger seed sizes resulted in a greater probability of recruitment, with further influences on species success including site aridity, taxonomic identity and species life form. Our findings suggest that investigations examining these predictive factors will yield more effective and informed restoration decision-making.

Climatic niche shift in the amphitropical disjunct grass Trichloris crinita.

Plant species disjunctions have attracted the interest of ecologists for decades. We investigated Trichloris crinita, a native C4 perennial grass with disjunct distribution between subtropical regions of North and South America, testing the hypothesis that the species has a similar realized climatic niche in both subcontinents. The climatic niche of T. crinita in North and South America was characterized and compared using presence records and five uncorrelated bioclimatic variables selected according to their ecological importance for the species. We used reciprocal modeling to make geographic projections of the realized niche within each subcontinent. Niche overlap between T. crinita distributions in North and South America was intermediate for the individual climatic variables and the multivariate space. In all cases the test of equivalence between climates inhabited by T. crinita indicated that the realized niche of the species differ significantly between subcontinents. Also, the similarity test showed that in the majority of cases the realized niche in both subcontinents was significantly different than that expected by chance. T. crinita occupied a greater diversity of environments in South than in North America, while in the latter its distribution was displaced to drier and warmer environments. The modeled geographic distribution using the actual occurrences of the species in North America did not accurately predict the distribution in South America, and vice versa. Together, these results led us to reject the hypothesis of similar niche of T. crinita in both subcontinents. This information may be useful to manage restoration efforts by presenting the suitable areas and climates for the species, and suggesting that translocation of individuals between subcontinents could only be recommended with caution because introduced genotypes can be potentially maladaptive, and could colonize sites actually not occupied by the species within each subcontinent.

Classification of EEG abnormalities in partial epilepsy with simultaneous EEG-fMRI recordings.

Scalp EEG recordings and the classification of interictal epileptiform discharges (IED) in patients with epilepsy provide valuable information about the epileptogenic network, particularly by defining the boundaries of the "irritative zone" (IZ), and hence are helpful during pre-surgical evaluation of patients with severe refractory epilepsies. The current detection and classification of epileptiform signals essentially rely on expert observers. This is a very time-consuming procedure, which also leads to inter-observer variability. Here, we propose a novel approach to automatically classify epileptic activity and show how this method provides critical and reliable information related to the IZ localization beyond the one provided by previous approaches. We applied Wave_clus, an automatic spike sorting algorithm, for the classification of IED visually identified from pre-surgical simultaneous Electroencephalogram-functional Magnetic Resonance Imagining (EEG-fMRI) recordings in 8 patients affected by refractory partial epilepsy candidate for surgery. For each patient, two fMRI analyses were performed: one based on the visual classification and one based on the algorithmic sorting. This novel approach successfully identified a total of 29 IED classes (compared to 26 for visual identification). The general concordance between methods was good, providing a full match of EEG patterns in 2 cases, additional EEG information in 2 other cases and, in general, covering EEG patterns of the same areas as expert classification in 7 of the 8 cases. Most notably, evaluation of the method with EEG-fMRI data analysis showed hemodynamic maps related to the majority of IED classes representing improved performance than the visual IED classification-based analysis (72% versus 50%). Furthermore, the IED-related BOLD changes revealed by using the algorithm were localized within the presumed IZ for a larger number of IED classes (9) in a greater number of patients than the expert classification (7 and 5, respectively). In contrast, in only one case presented the new algorithm resulted in fewer classes and activation areas. We propose that the use of automated spike sorting algorithms to classify IED provides an efficient tool for mapping IED-related fMRI changes and increases the EEG-fMRI clinical value for the pre-surgical assessment of patients with severe epilepsy.

Partial duplication of 18q including a distal critical region for Edwards Syndrome in a patient with normal phenotype and oligoasthenospermia: case report.

Several authors have attempted to construct a phenotype map for duplications of different portions of chromosome 18 to identify a possible critical region (CR) for Edwards Syndrome. Partial duplications of 18q have been reported in the literature involving the distal CR in patients with some clinical features of Edwards Syndrome. Here, we describe a phenotypically normal male with a large duplication on chromosome 18 that involves the proposed distal CR. The lack of clinical features is remarkable, except for pathological semen analysis, which suggests that terminal 17.4 Mb of 18q do not contain the Edwards Syndrome CR. Alternatively, unknown modifier factors or undetected somatic mosaicism might cause incomplete penetrance of this duplication.

Aridity and grazing as convergent selective forces: an experiment with an Arid Chaco bunchgrass.

It has been proposed that aridity and grazing are convergent selective forces: each one selects for traits conferring resistance to both. However, this conceptual model has not yet been experimentally validated. The aim of this work was to experimentally evaluate the effect of aridity and grazing, as selective forces, on drought and grazing resistance of populations of Trichloris crinita, a native perennial forage grass of the Argentinean Arid Chaco region. We collected seeds in sites with four different combinations of aridity and grazing history (semiarid/ subhumid x heavily grazed/lightly grazed), established them in pots in a common garden, and subjected the resulting plants to different combinations of drought and defoliation. Our results agreed with the convergence model. Aridity has selected T. crinita genotypes that respond better to drought and defoliation in terms of sexual reproduction and leaf growth, and that can evade grazing due to a lower shoot: root ratio and a higher resource allocation to reserves (starch) in stem bases. Similarly, grazing has selected genotypes that respond better to drought and defoliation in terms of sexual reproduction and that can evade grazing due to a lower digestibility of leaf blades. These results allow us to extend concepts of previous models in plant adaptation to herbivory to models on plant adaptation to drought. The only variable in which we obtained a result opposite to predictions was plant height, as plants from semiarid sites were taller (and with more erect tillers) than plants from subhumid sites; we hypothesize that this result might have been a consequence of the selection exerted by the high solar radiation and soil temperatures of semiarid sites. In addition, our work allows for the prediction of the effects of dry or wet growing seasons on the performance of T. crinita plants. Our results suggest that we can rely on dry environments for selecting grazing-resistant genotypes and on high grazing pressure history environments for selecting drought-resistant ones.

Neurofibromatosis: Neurofibroma plexiforme localizado en mama. A propósito de un caso / Neurofibromatosis: Plexiform Neurofibroma Localized In Mamma. A Propos Of A Case

La Neurofibromatosis fue descrita por Von Recklinghausen en 1882. Es una genodermatosis autosómica dominante con alta penetrancia, expresividad variable y curso progresivo; se calcula que en el 50% de los casos se deben a mutaciones espontáneas (de novo), con una incidencia de 1/3000 recién nacidos. Clínicamente se manifiesta por el compromiso de los tejidos derivados del neuroectodermo y mesodermo. Muestra alteraciones oculares, neurológicas, de partes blandas, cutáneas, óseas, endocrinológicas y lesiones viscerales. En la actualidad se admiten dos formas clínicas principales: la Neurofibromatosis clásica o de tipo I que representa el 85-90 % de los casos y la Neurofibromatosis tipo II (Neurofibromatosis del acústico bilateral) muy poco frecuente.

The Neurofibromatosis was described by von Recklinghausen in 1882. It is a dominant autosomic genodermatosis with a high penetration, variable clinic and progressive course; it is calculate, that in 50% of the cases the origin is a spontaneous mutations (novo). The incidence is 1/3000 newly born. The clinical manifestations are: the compromise of tissues derived from neuroectoderm and mesoderm. It also has ocular symptoms, visceral injuries, neurological alterations and endocrinological pathologies. Soft pars, cutaneous tissue and bones are affected. At the present time two main clinical forms are admitted: the Classic Neurofibromatosis or type I, that represents 85-90% of the cases and the Neurofibromatosis type II (Neurofibromatosis of the bilateral hearing aid) that it ´s not so frequent.

Rare chromosomal complement of trisomy 21 in a boy conceived by IVF and cryopreservation.

This report describes a case of mosaic Down syndrome due to an unusual karyotype in a patient conceived by assisted reproductive techniques and cryopreservation. The chromosomal complement consists of two different cell lines, one predominantly trisomic with a derivative chromosome due to a Robertsonian translocation (21;21) and another carrying a ring chromosome 21. The present work analyses the different mechanisms that could have led to mosaicism.

Submicroscopic duplication of the Wolf-Hirschhorn critical region with a 4p terminal deletion.

Chromosomal rearrangements in the short arm of chromosome 4 can result in 2 different clinical entities: Wolf-Hirschhorn syndrome (WHS), characterized by severe growth delay, mental retardation, microcephaly, 'Greek helmet' facies, and closure defects, or partial 4p trisomy, associated with multiple congenital anomalies, mental retardation, and facial dysmorphisms. We present clinical and laboratory findings in a patient who showed a small duplication in 4p16.3 associated with a subtle terminal deletion in the same chromosomal region. GTG-banding analyses, multiplex ligation-dependent probe amplification analyses, and studies by array-based comparative genomic hybridization were performed. The results of the analyses revealed a de novo 1.3 Mb deletion of the terminal 4p and a 1.1 Mb duplication in our patient, encompassing the WHS critical region. Interestingly, this unusual duplication/deletion rearrangement results in an intermediate phenotype that shares characteristics of the WHS and the 4p trisomy syndrome. The use of novel technologies in the genetic diagnosis leads to the description of new clinical syndromes; there is a growing list of microduplication syndromes. Therefore, we propose that overexpression of candidate genes in WHS (WHSC1, WHSC2 and LETM1) due to a duplication causes a clinical entity different to both the WHS and 4p trisomy syndrome.

Corpus callosum abnormalities and the controversy about the candidate genes located in 1q44.

Submicroscopic deletions of 1q44-qter cause severe mental retardation, profound growth retardation, microcephaly and corpus callosum hypo/agenesis in most patients. At least 3 intervals in 1q44 have been described as critical regions containing genes leading to corpus callosum abnormalities. In this report we describe a patient with a de novo small interstitial 1q44 deletion of 1,152 kb detected with 44K oligonucleotide array-CGH (44K Agilent Technologies) and a mild phenotype lacking corpus callosum abnormalities. The first deleted oligonucleotide was located at 242.638 Mb (within the ADSS gene), and the last deleted oligonucleotide at 243.791 Mb (within the KIF26B gene). The clinical and molecular findings of the patient here reported remain consistent with a role for the AKT3 or ZNF238 genes in corpus callosum development.

What is the real shape of extracellular spikes?

We show that the standard filters used for on-line spike detection in most hardware acquisition systems introduce distortions in the recorded spike shapes. This is because on-line spike detection is done after band pass filtering the data with causal filters. As illustrated with three clusters of spike shapes from a real single cell recording in a human subject, causal filtering can create a spurious negative rebound and a smooth looking appearance of the spikes. We also show that these filtering distortions can make artifacts look similar to real spikes.

Duplication of the Williams-Beuren critical region: case report and further delineation of the phenotypic spectrum.

Only 12 patients with a duplication of the Williams-Beuren critical region (WBCR) have been reported to date, with variable developmental, psychomotor and language delay, in the absence of marked dysmorphic features. In this paper we present a new WBCR microduplication case, which supports the wide variability displayed by this duplication in the phenotype. The WBCR microduplication may be associated with autistic spectrum disorder, but most reported cases do not show this behavioural disorder, or may even show a hypersociable personality, as with our patient. From the present case and a review of the 12 previously described, we conclude that the phenotype associated with duplication of WBCR can affect the same domains as WBCR deletion, but that they cluster near the polar ends of social relationship (autism-like v hypersociability), language (expressive language impairment v "cocktail party" speech), visuospatial (severe v normal), mental retardation (severe v mild) and dysmorphic (severe v mild) features.

Sparse but not 'grandmother-cell' coding in the medial temporal lobe.

Although a large number of neuropsychological and imaging studies have demonstrated that the medial temporal lobe (MTL) plays an important role in human memory, there are few data regarding the activity of neurons involved in this process. The MTL receives massive inputs from visual cortical areas, and evidence over the last decade has consistently shown that MTL neurons respond selectively to complex visual stimuli. Here, we focus on how the activity patterns of these cells might reflect the transformation of visual percepts into long-term memories. Given the very sparse and abstract representation of visual information by these neurons, they could in principle be considered as 'grandmother cells'. However, we give several arguments that make such an extreme interpretation unlikely.

Human single-neuron responses at the threshold of conscious recognition.

We studied the responses of single neurons in the human medial temporal lobe while subjects viewed familiar faces, animals, and landmarks. By progressively shortening the duration of stimulus presentation, coupled with backward masking, we show two striking properties of these neurons. (i) Their responses are not statistically different for the 33-ms, 66-ms, and 132-ms stimulus durations, and only for the 264-ms presentations there is a significantly higher firing. (ii) These responses follow conscious perception, as indicated by the subjects' recognition report. Remarkably, when recognized, a single snapshot as brief as 33 ms was sufficient to trigger strong single-unit responses far outlasting stimulus presentation. These results suggest that neurons in the medial temporal lobe can reflect conscious recognition by "all-or-none" responses.

Decoding visual inputs from multiple neurons in the human temporal lobe.

We investigated the representation of visual inputs by multiple simultaneously recorded single neurons in the human medial temporal lobe, using their firing rates to infer which images were shown to subjects. The selectivity of these neurons was quantified with a novel measure. About four spikes per neuron, triggered between 300 and 600 ms after image onset in a handful of units (7.8 on average), predicted the identity of images far above chance. Decoding performance increased linearly with the number of units considered, peaked between 400 and 500 ms, did not improve when considering correlations among simultaneously recorded units, and generalized to very different images. The feasibility of decoding sensory information from human extracellular recordings has implications for the development of brain-machine interfaces.

¿Está justificado el uso de estatinas en todo paciente con diabetes? / Is the use of statins justified in all diabetic patients?

Actualmente se considera la diabetes mellitus como uno de los más importantes problemas sociosanitarios en todo el mundo. Está bien establecida la correlación entre la hiperglucemia y los episodios cardiovasculares. Entre los factores de riesgo de tales episodios, cabe destacar la dislipemia y la hiperactivación plaquetaria, ambos asociados a la diabetes, cuyo conocimiento intenta poner al día la presente revisión. Dado que se ha descrito que las estatinas, además de su conocido efecto sobre los lípidos plasmáticos, también ejercen una cierta acción sobre la activación plaquetaria, puede plantearse la pregunta de si resultaría efectiva su administración, incluso a los pacientes diabéticos con una mínima dislipemia. La bibliografía revisada pone de manifiesto la falta de acuerdo entre los diversos autores respecto a qué estatinas, en qué dosis, durante cuánto tiempo y a qué tipo de pacientes deben administrarse para alcanzar una mejor protección contra los episodios trombóticos más frecuentes en la diabetes

Today, diabetes mellitus is considered to be one of the most important public health problems around the world. The correlation between hyperglycemia and cardiovascular events has been well established. Among the risk factors for these events, dyslipidemia and platelet hyperactivity are of special importance because both are associated with diabetes. The objective of the present review is to provide an update on these risk factors. In addition to the well-known effect of statins on plasma lipid levels, they have also been reported to exert a certain action on platelet activation. For this reason, we considered the question as to whether it would be of interest to administer statins even to diabetic patients with minimum dyslipidemia. The literature reviewed demonstrates the lack of agreement among the different authors in relation to which statin should be administered and at what dose, for how long and to what type of patients in order to achieve better protection against thrombotic events, which occur more frequently in diabetic patients

Cribado de trisomía 21 en el primer trimestre mediante el test combinado. Valoración de su efectividad / First trimester combined screening test for trisomy 21. Effectiveness evaluation

Introducción. Valorar la efectividad del cribado combinado del primer trimestre del síndrome de Down en términos de tasa de detección (TD) y tasa de falsos positivos (TFP). Pacientes y métodos. Estudio retrospectivo de 6.269gestantes con fetos únicos cribadas en el Hospital La Fe de Valencia entre 2003-2005. El punto de corte fue de 1/270. Se revisaron los cariotipos obtenidos de los métodos invasivos y de sangre periférica de recién nacidos del período correspondiente. Resultados. En nuestro estudio el porcentaje de mujeresmayores de 35 años representó el 11,23% de la poblaciónasistida. La tasa de cribados positivos fue del 2,98%. Seha obtenido una TD del 90% y una TFP del 3%. Conclusiones. La estimación del riesgo para identificarpacientes de alto riesgo de aneuploidías mediante el cribado combinado que se está utilizando en nuestro hospital en el primer trimestre de la gestación se ha mostrado aplicable, eficaz y eficiente

Objective. To asses the effectiveness of first trimestercombined screening test for prenatal detection ofDown’s syndrome, in terms of detection rate (DR) andfalse positive rate (FPR).Subjects and methods. Retrospective study on 6,269of pregnant women with screening test carried out atHospital La Fe in Valencia between 2003-2005. We haveincluded only gestation with unique fetuses. Cut-off value was 1/270 to consider pregnancies in high risk ofaneuploidy. Karyotypes of invasive methods and peripheralblood of the corresponding period have been reviewed.Results. Our study showed that women older 35 yearsof the attended population represented 11.23%. The positive screening rate was 2.98%. A detection rate for trisomy 21 of 90% has been obtained and a false positiverate of 3%.Conclusions. The estimation of risk by mean of thecombined first trimester test used in our Hospital hasshown applicable, effective and efficient to identify patients at high risk of aneuploidies