Characterization of algal community composition and structure from the nearshore environment, Lake Tahoe (United States).

Periphyton assemblages from the nearshore environment of the west (California) side of Lake Tahoe, were analyzed to determine their taxonomic composition and community structure across habitats and seasons. Lake Tahoe is the second deepest lake in the US and an iconic oligotrophic subalpine lake with remarkable transparency. It has experienced offshore cultural eutrophication since the 1960s with observations of nuisance nearshore algal growth since the mid 2000s attributed to anthropogenic stressors. Samplings from November 2019-September 2020 provide useful snapshots against which older monitoring may be contextualized. A voucher flora, complete with descriptions, photo-documentation and referencing to species concepts employed, was created as a method of providing reproducible identification and enumeration of algal species, and more seamless reconciliation of detailed taxonomic data with future monitoring projects. The eulittoral zone (0-2 m) is seasonally dominated by elongate araphid (Synedra, Ulnaria) and stalked or entubed diatoms (Gomphonema, Cymbella, Encyonema). The sublittoral zone (>2 m) is dominated by a nitrogen-fixing Epithemia-cyanobacteria assemblage with less seasonal changes in dominance and composition that expanded to impinge on the 2 m depths of the eulittoral zone in the Fall. Sublittoral epipsammic samples, despite their proximity to rocks, had a very distinct diatom composition and high species dominance, similar to what was seen in the Fall eulittoral samples, with high numbers of Staurosirella chains and small biraphid diatoms. The deeper samples at 30 and 50 m contained high numbers of live Epithemia, and indicate a thriving sublittoral assemblage at these greater depths, but with less biomass. The 2019-20 data show many of the same diatom taxa observed in the 1970's and 1980's but with changes in species dominance. Notably, there was less of the green alga Mougeotia, when compared to the 1970's data, and a higher dominance by nitrogen fixing Epithemia in the sublittoral zone, persisting year-round. These new data show roughly double the algal species biodiversity that had been documented previously in the Lake Tahoe nearshore, and is largely attributed to the methods employed. Adopting these new methods in future monitoring efforts should improve harmonization of taxonomic data and help advance our knowledge of the contributions to nearshore cultural eutrophication.

Abundance does not predict extinction risk in the fossil record of marine plankton.

A major premise of ecological neutral theory is that population size is inversely related to extinction risk. This idea is central to modern biodiversity conservation efforts, which often rely on abundance metrics to partially determine species extinction risk. However, limited empirical studies have tested whether extinction is indeed more probable for species with low abundances. Here we use the fossil record of Neogene radiolaria to test the relationship between relative abundance and longevity (time from first to last occurrence). Our dataset includes abundance histories for 189 polycystine radiolarian species from the Southern Ocean, and 101 species from the tropical Pacific. Using linear regression analyses, we show that neither maximum nor average relative abundance are significant predictors of longevity in either oceanographic region. This suggests that neutral theory fails to explain the plankton ecological-evolutionary dynamics we observe. Extrinsic factors are likely more important than neutral dynamics in controlling radiolarian extinction.

Grouping behavior in a Triassic marine apex predator.

Marine tetrapods occupy important roles in modern marine ecosystems and often gather in large aggregations driven by patchy prey distribution,1,2 social or reproductive behaviors,3,4 or oceanographic factors.5 Here, we show that similar grouping behaviors evolved in an early marine tetrapod lineage, documented by dozens of specimens of the giant ichthyosaur Shonisaurus in the Luning Formation in West Union Canyon, Nevada, USA.6,7 A concentration of at least seven skeletons closely preserved on a single bedding plane received the bulk of previous attention. However, many more specimens are preserved across ∼106 square meters and ∼200 stratigraphic meters of outcrop representing an estimated >105-6 years. Unlike other marine-tetrapod-rich deposits, this assemblage is essentially monotaxic; other vertebrate fossils are exceptionally scarce. Large individuals are disproportionately abundant, with the exception of multiple neonatal or embryonic specimens, indicating an unusual demographic composition apparently lacking intermediate-sized juveniles or subadults. Combined with geological evidence, our data suggest that dense aggregations of Shonisaurus inhabited this moderately deep, low-diversity, tropical marine environment for millennia during the latest Carnian Stage of the Late Triassic Period (237-227 Ma). Thus, philopatric grouping behavior in marine tetrapods, potentially linked to reproductive activity, has an antiquity of at least 230 million years.

Analysis of the variables involved in the time to resolution of metabolic parameters in adults with diabetic ketoacidosis / [Análisis de las variables involucradas en el tiempo de resolución de los parámetros metabólicos en adultos con cetoacidosis diabética.]

Introduction: Diabetic ketoacidosis (DKA) is a life-threatening complication characterized by hyperglycemia, metabolic acidosis, and ketonemia. Although the time to resolution of DKA has been estimated at 12 to 18 hours, the factors that could prolong it have not been fully studied. Methods: Retrospective study of medical records of adult patients admitted to the general ward with a diagnosis of DKA. They were classified according to severity as mild, moderate and severe. The time to resolution of crisis (TRC) was defined as that necessary until normalization of metabolic parameters. A logistic regression analysis was performed to evaluate the association between TRC>12 hours and continuous variables. ROC analysis and survival analysis were performed using a Cox regression model. Results: 85 patients were studied. 48.23% presented severe DKA. The TRC was 14 hours, being higher in severe DKA. Patients with TRC>12 hours had a lower pH and HCO3-, and a higher anion gap, white blood cells, and volume of crystalloids used. Logistic regression analysis showed that pH and crystalloid volume correlated with TRC>12 hours. ROC analysis determined a pH cutoff value of 7.13 for TRC>12 hours (sensitivity 77%, specificity 88%). The Cox regression showed that a pH<7.13 on admission is associated with a higher TRC (HR 3.30). Conclusion: A pH lower than 7.13 at the time of hospital admission identifies patients with DKA who will need a longer time to resolve their metabolic parameters.

Introducción: La cetoacidosis diabética (CAD) es una complicación potencialmente mortal caracterizada por hiperglucemia, acidosis metabólica y cetonemia. Aunque el tiempo para la resolución de la CAD se ha estimado en 12 a 18 horas, los factores que podrían prolongarlo no se han estudiado con exhaustividad. Métodos: Estudio retrospectivo de historias clínicas de pacientes adultos admitidos a sala general con diagnóstico de CAD. Se clasificaron según la severidad en leve, moderada y severa. El tiempo de resolución de la crisis (TRC) se definió como aquel necesario hasta normalización de parámetros metabólicos. Se realizó un análisis de regresión logística para evaluar la asociación entre TRC>12 horas y variables continuas. Se realizó un análisis ROC y un análisis de supervivencia utilizando un modelo de regresión de Cox. Resultados: Se estudiaron 85 pacientes. El 48.23% presentó CAD severa. El TRC fue de 14 horas, siendo mayor en CAD severa. Los pacientes con TRC>12 horas presentaron menor pH y HCO3, y mayor anión gap, glóbulos blancos y volumen de cristaloides utilizados. El análisis de regresión logística demostró que el pH y el volumen de cristaloides correlacionaron con TRC>12 horas. El análisis ROC determinó un valor de corte de pH de 7.13 para TRC>12 horas (sensibilidad 77%, especificidad 88%). La regresión de Cox demostró que un pH <7.13 al ingreso se asocia a mayor TRC (HR 3.30). Conclusión: Un pH menor a 7.13 al momento de admisión hospitalaria identifica a pacientes con CAD que necesitarán un mayor tiempo para resolver sus parámetros metabólicos.

Late Neogene Lophophaenidae (Nassellaria, Radiolaria) from the eastern equatorial Pacific.

Lophophaenidae is a clade of polycystine radiolarians that was highly abundant and diverse in the Late NeogeneRecent eastern equatorial Pacific (EEP). Despite their importance in fossil plankton assemblages, lophophaenids have been neglected because of their generally small size, complex morphology, and weak taxonomic framework. These challenges have left many lophophaenid concepts poorly defined or lacking formal description. Here we address this with a review of 101 lophophaenid taxa observed in EEP Middle MioceneRecent marine sediments. We discuss existing lophophaenid genera Amphiplecta Haeckel 1881, Arachnocorallium Haeckel 1887, Arachnocorys Haeckel 1860, Botryopera Haeckel 1887, Ceratocyrtis Btschli 1882, Lithomelissa Ehrenberg 1847, Lophophaena Ehrenberg 1847, and Peromelissa Haeckel 1881, including full species lists. We describe Pelagomanes n. gen., 23 new species: Amphiplecta kikimorae n. sp., Arachnocorys jorogumoae n. sp., Botryopera amabie n. sp., Botryopera babayagae n. sp., Botryopera bolotniki n. sp., Ceratocyrtis? chimii n. sp., Ceratocyrtis vila n. sp., Lithomelissa alkonost n. sp., Lithomelissa babai n. sp., Lithomelissa dybbuki n. sp., Lithomelissa sirin n. sp., Lophophaena arie n. sp., Lophophaena casperi n. sp., Lophophaena domovoi n. sp., Lophophaena gozui n. sp., Lophophaena ikiryo n. sp., Lophophaena ikota n. sp., Lophophaena kaonashii n. sp., Lophophaena leshii n. sp., Lophophaena rusalkae n. sp., Lophophaena shishigae n. sp., Lophophaena ushionii n. sp., and Pelagomanes ibburi n. sp., and one new subspecies, Arachnocorys pentacantha wanii n. subsp. In addition, we document 35 taxa in open nomenclature, and revise generic assignments of 10 species. The names of 32 previously-described species are upheld, but with clarified synonymies, discussion, and illustrations. This work contributes a practical framework for identifying tropical Late NeogeneRecent lophophaenid taxa, and demonstrates their rich morphological diversity.

Marine plankton show threshold extinction response to Neogene climate change.

Ongoing climate change is predicted to trigger major shifts in the geographic distribution of marine plankton species. However, it remains unclear whether species will successfully track optimal habitats to new regions, or face extinction. Here we show that one significant zooplankton group, the radiolaria, underwent a severe decline in high latitude species richness presaged by ecologic reorganization during the late Neogene, a time of amplified polar cooling. We find that the majority (71%) of affected species did not relocate to the warmer low latitudes, but went extinct. This indicates that some plankton species cannot track optimal temperatures on a global scale as assumed by ecologic models; instead, assemblages undergo restructuring and extinction once local environmental thresholds are exceeded. This pattern forewarns profound diversity loss of high latitude radiolaria in the near future, which may have cascading effects on the ocean food web and carbon cycle.

Historical ecology reveals landscape transformation coincident with cultural development in central Italy since the Roman Period.

Knowledge of the direct role humans have had in changing the landscape requires the perspective of historical and archaeological sources, as well as climatic and ecologic processes, when interpreting paleoecological records. People directly impact land at the local scale and land use decisions are strongly influenced by local sociopolitical priorities that change through time. A complete picture of the potential drivers of past environmental change must include a detailed and integrated analysis of evolving sociopolitical priorities, climatic change and ecological processes. However, there are surprisingly few localities that possess high-quality historical, archeological and high-resolution paleoecologic datasets. We present a high resolution 2700-year pollen record from central Italy and interpret it in relation to archival documents and archaeological data to reconstruct the relationship between changing sociopolitical conditions, and their effect on the landscape. We found that: (1) abrupt environmental change was more closely linked to sociopolitical and demographic transformation than climate change; (2) landscape changes reflected the new sociopolitical priorities and persisted until the sociopolitical conditions shifted; (3) reorganization of new plant communities was very rapid, on the order of decades not centuries; and (4) legacies of forest management adopted by earlier societies continue to influence ecosystem services today.

Repetition blindness and homophone blindness in young and older adults.

We tested age effects on repetition blindness (RB), defined as the reduced probability of reporting a target word following presentation of the same word in a rapidly presented list. We also tested age effects on homophone blindness (HB), in which the first word is a homophone of the target word rather than a repeated word. Thirty young and 28 older adults viewed rapidly presented lists of words containing repeated, homophone, or unrepeated word pairs and reported all of the words immediately after each list. Older adults exhibited a greater degree of RB and HB than young adults using a conditional scoring method that provides certainty that blindness has occurred. The existence of RB and HB for both age groups, and increased blindness for older compared to young adults, supports predictions of a binding theory that has successfully accounted for a wide range of phenomena in cognitive aging.

The effects of age on using prosody to convey meaning and on judging communicative effectiveness.

We tested the effects of aging on the use of prosody to convey meaning and the ability to monitor communicative effectiveness. Participants read aloud ambiguous sentences with the goal of clearly communicating one designated meaning. Young and older adults produced intonational boundaries consistent with the designated meaning equally often, but listener judgments indicated that older adults disambiguated the sentences more often than chance and young adults did so only marginally more often than chance. Young adults believed they communicated their message clearly, and older adults evaluated their own communication even more favorably. Participants were more confident for structurally ambiguous sentences than for lexically ambiguous sentences (which cannot be differentiated through prosody), and older adults demonstrated more overconfidence than young adults for both types of ambiguous sentences.

Engaging patients, clinicians and health funders in weight management: the Counterweight Programme.

BACKGROUND: The Counterweight Programme provides an evidence based and effective approach for weight management in routine primary care. Uptake of the programme has been variable for practices and patients. Aim. To explore key barriers and facilitators of practice and patient engagement in the Counterweight Programme and to describe key strategies used to address barriers in the wider implementation of this weight management programme in UK primary care. METHODS: All seven weight management advisers participated in a focus group. In-depth interviews were conducted with purposeful samples of GPs (n = 7) and practice nurses (n = 15) from 11 practices out of the 65 participating in the programme. A total of 37 patients participated through a mixture of in-depth interviews (n = 18) and three focus groups. Interviews and focus groups were analysed for key themes that emerged. RESULTS: Engagement of practice staff was influenced by clinicians' beliefs and attitudes, factors relating to the way the programme was initiated and implemented, the programme content and organizational/contextual factors. Patient engagement was influenced by practice endorsement of the programme, clear understanding of programme goals, structured proactive follow-up and perception of positive outcomes. CONCLUSIONS: Having a clear understanding of programme goals and expectations, enhancing self-efficacy in weight management and providing proactive follow-up is important for engaging both practices and patients. The widespread integration of weight management programmes into routine primary care is likely to require supportive public policy.