Search

Objective: To assess the relationship between ADHD and performance of household chores. Method: A 72-question online questionnaire was developed to collect demographic/clinical information as well as parents’ assessment of their child’s performance of self-care (SC) and family-care (FC) chores. Results: The sample consists of 797 primary caregivers of children with ADHD. The overwhelming majority of parents believed that ADHD to some extent affected their child’s ability to independently and satisfactorily complete SC and FC chores. An inverse relationship was noted between parent ratings of a child’s ability to do chores independently and satisfactorily and the likelihood they believed ADHD affected chore performance. There was no difference in chore performance between children with or without co-morbid oppositional defiant disorder. Conclusion: Given that household routines, including chores, play an important role in children’s development and psychosocial adjustment, clinicians must be sensitive to the adverse impact that ADHD may have in this regard.

Light and scanning electron microscope observations are made on some members of the section Obtusae in the genus Nitzschia (Bacillariales, Bacillariophyceae). We use type and other material derived from both the National Water Quality Assessment (NAWQA) program in the USA and from Egypt to assess five different taxa, two of which are described as new to science (Nitzschia lowei, sp. nov., Nitzschia potapovae, sp. nov.) and another is made as a new nomenclatural combination (Nitzschia kurzeana var. multistriata (Hohn) comb. nov.). Other names used in the literature for some of these taxa are considered and discussed. Based on the features of sigmoid valves, eccentric raphe not in an elevated keel, lack of a conopeum, strongly bent, elongated external proximal raphe ends extending onto the valve face, and presence of a differentiated central 'nodule', members of this group are clearly differentiated from the generitype of Nitzschia and most other recognized sections of the genus.

Consistent identification of diatoms is a prerequisite for studying their ecology, biogeography, and successful application as environmental indicators. However, taxonomic consistency among observers has been difficult to achieve, because taxonomic information is scattered across numerous literature sources, presenting challenges to the diatomist. First, literature is often inaccessible because of cost, or its location in journals that are not widely circulated. Second, taxonomic revisions of diatoms are taking place faster than floras can be updated. Finally, taxonomic information is often contradictory across literature sources. These issues can be addressed by developing a content creation community dedicated to making taxonomic, ecological, and image-based data freely available for diatom researchers. Diatoms.org represents such a content curation community, providing open, online access to a vast amount of recent and historical information on North American diatom taxonomy and ecology. The content curation community aggregates existing taxonomic information, creates new content, and provides feedback in the form of corrections and notice of literature with nomenclatural changes. The website not only addresses the needs of experienced diatom scientists for consistent identification, but is also designed to meet users at their level of expertise, including engaging the lay public in the importance of diatom science. The website now contains over 1000 species pages contributed by over 100 content contributors, from students to established scientists. The project began with the intent to provide accurate information on diatom identification, ecology, and distribution using an approach that incorporates engaging design, user feedback, and advanced data access technology. In retrospect, the project that began as an "extended electronic book" has emerged not only as a means to support taxonomists, but for practitioners to communicate and collaborate, expanding the size of and benefits to the content curation community. In this paper, we outline the development of diatoms.org, document key elements of the project, examine ongoing challenges, and consider the unexpected emergent properties, including the value of diatoms.org as a source of data. Ultimately, if the field of diatom taxonomy, ecology, and biodiversity is to be relevant, a new generation of taxonomists needs to be trained and employed using new tools. We propose that diatoms.org is in a key position to serve as a hub of training and continuity for the study of diatom biodiversity and aquatic conditions.

While describing the species Tetracyclus hinziae I. Bishop & Spaulding (2015, p. 200), it was noticed that the basionym and type specimens of the similar species Tetracyclus rupestre was unclear. This short note addresses those concerns.

Current fixed-count enumeration methods for benthic diatoms are likely inadequate for most research and monitoring objectives. These methods underestimate taxa richness and may fail to dete...

Benthic cyanobacteria are widespread in streams and rivers and have the potential to release toxins. In large numbers, these microorganisms and their toxins present a risk to human health. Cyanobacterial abundance in stream biofilms is typically related to single or a limited set of environmental factors, mainly light availability, water temperature, and nutrient concentrations. However, these factors may act synergistically with watershed characteristics and other stressors, such as anthropogenic pollutants, to affect cyanobacteria. We investigated the influence of multiple regional and local variables on the abundance of benthic cyanobacterial genera in streams using all subsets generalized additive modeling. We examined watershed factors (topography, geology, and climate) alongside in-stream factors (geomorphology, hydrology, pH, specific conductance, nutrients, organic contaminants, and dissolved metals) from 76 sites along an urban gradient in the northeast United States. Each genus responded to a distinct combination of environmental variables, demonstrating strong intergeneric variation in environmental selection of realized niches. Four of the 7 potentially toxigenic genera that we modeled were positively influenced by water temperature or nutrients. Nonetheless, watershed characteristics, streamflow, and/or other water quality pollutants were equally or more influential for the potentially toxigenic genera. Additionally, the relationships between cyanobacterial abundance and environmental factors varied in shape and direction across many genera. In particular, with increasing concentrations of herbicides, polychlorinated biphenyls, or metals, the abundance of roughly half of the affected genera decreased, while the others increased. These results likely demonstrate novel toxic effects of the pollutants on cyanobacterial genera in the environment, while indicating that unmeasured biotic interactions may lead to positive responses for other genera. Our results emphasize the need to consider variables beyond those that are most frequently measured or implicated (e.g., water temperature and nutrients) to more fully understand the environmental conditions that influence the distributions and abundance of potentially harmful cyanobacteria.

The non-marine diatom flora of the Antarctic Continent includes several endemic taxa recorded over the past 100 years. One of these taxa, Navicula adminensis D.Roberts & McMinn, was described from the Vestfold Hills, East Antarctica. Detailed light and scanning electron microscopy observations have shown that based on its morphological features, the species does not belong to the genus Navicula sensu stricto. To determine the most closely related genera to N. adminensis, the morphological features of Adlafia, Kobayasiella, Envekadea, Stenoneis, Berkeleya, Climaconeis, and Parlibellus were compared with those of N. adminensis. Although each of these genera shows one or more similar features, none of them accommodates the salient morphological characteristics of N. adminensis. Therefore, a new genus, Sabbea gen. nov., is herein described, and Navicula adminensis is formally transferred to the new genus as Sabbea adminensis comb. nov. The genus Sabbea is characterized by uniseriate striae composed of small, rounded areolae occluded externally by individual hymenes, a rather simple raphe structure with straight, short proximal ends and short terminal raphe fissures, open girdle bands with double perforation and a very shallow mantle.

Mountain lakes are often situated in protected natural areas, a feature that leads to their role as sentinels of global environmental change. Despite variations in latitude, mountain lakes share many features, including their location in catchments with steep topographic gradients, cold temperatures, high incident solar and ultraviolet radiation (UVR), and prolonged ice and snow cover. These characteristics, in turn, affect mountain lake ecosystem structure, diversity, and productivity. The lakes themselves are mostly small, and up until recently, have been characterized as oligotrophic. This paper provides a review and update of the growing body of research that shows that sediments in remote mountain lakes archive regional and global environmental changes, including those linked to climate change, altered biogeochemical cycles, and changes in dust composition and deposition, atmospheric fertilization, and biological manipulations. These archives provide an important record of global environmental change that pre-dates typical monitoring windows. Paleolimnological research at strategically selected lakes has increased our knowledge of interactions among multiple stressors and their synergistic effects on lake systems. Lakes from transects across steep climate (i.e., temperature and effective moisture) gradients in mountain regions show how environmental change alters lakes in close proximity, but at differing climate starting points. Such research in particular highlights the impacts of melting glaciers on mountain lakes. The addition of new proxies, including DNA-based techniques and advanced stable isotopic analyses, provides a gateway to addressing novel research questions about global environmental change. Recent advances in remote sensing and continuous, high-frequency, limnological measurements will improve spatial and temporal resolution and help to add records to spatial gaps including tropical and southern latitudes. Mountain lake records provide a unique opportunity for global scale assessments that provide knowledge necessary to protect the Earth system.

The late Eocene Florissant Formation in central Colorado is a rich and diverse continental Lagerstätte yielding well-preserved fossil assemblages from lacustrine and fluvial facies. This investigation focused on the lacustrine facies at Clare’s Quarry and used biotic and abiotic evidence to characterize aspects of the lake and processes that resulted in the accumulation and preservation of the host rock and its fossils. Autecology of modern analogs representing the fossil diatom taxa was used to augment sedimentary data in characterizing the lake, propose peripheral habitats within the catchment area, and suggest a terrestrial source for mudstone units. The sedimentary and stratigraphic record at the study site reveals a lake with sufficient depth to allow bottom waters to remain isolated and anoxic for long periods. Sediments that accumulated in the lake produced distinct lacustrine lithofacies that are interpreted as representing at least three modes of origin: stable lake, pyroclastic, and mud turbidite sedimentation. Slow, suspension settling of fine clays and volcanic ash into a moderately deep, stable lake resulted in laminated shales. These laminated shales contain frustules of diatoms from planktic and benthic lake habitats; diatoms transported into the lake from streams and wetlands; fish, mollusks, ostracods, and insects; and plants from marginal and upslope environments. Intermittent volcanic eruptions produced air-fall ash and granular tuff that accumulated as interbeds within the lake shales. Periods of stable lake sedimentation were frequently interrupted by rapid influxes of suspended fine clays, perhaps as mud-dominated turbidites that prograded into the lake at intervals of high runoff triggered by climatic, volcanic, or tectonic events.

Environmental programs in the United States face technical challenges that inhibit the ability to use diatoms in water quality monitoring and assessment projects. Specifically, inconsistent taxonomy can obscure diatom responses to environmental variables. Problems are the result of (1) limited access to a common set of taxonomic references, especially those that are geographically relevant, (2) inefficient enumeration protocols, (3) lack of complete and transparent documentation of taxa, and (4) limited opportunities for continued education, training, and knowledge sharing. However, robust resources and practices are available to improve diatom data quality and interpretation. Several resources improve diatom data quality, including a publicly accessible taxonomic reference (diatoms.org) and recommended practices. These practices include adoption of the voucher floras, random sample assignment, replicate microscope slides, and improved quality control. Finally, the Society for Freshwater Science Diatom Taxonomic Certification Committee is developing educational materials and certification exams to support practitioner training and to increase the diatom research knowledge base. The resources and practices in this article are broadly applicable to improving basic and applied research on diatoms worldwide.

Inconsistency in taxonomic identification and analyst bias impede the effective use of diatom data in regional and national stream and lake surveys. In this study, we evaluated the effect of existing protocols and a revised protocol on the precision of diatom species counts. The revised protocol adjusts five elements of sample preparation, taxon identification and enumeration, and quality control (QC) samples. We used six independent datasets to assess the effect of the adjustments on analytical outcomes. The first dataset was produced by five analysts from three laboratories following a standard protocol (Charles et al. 2002). The remaining datasets were produced by 2-3 analysts in 1-3 laboratories following a revised protocol. The revised protocol included the following modifications: 1) use of Battarbee settling chambers to prepare coverslips, 2) development of coordinated pre-count voucher floras based on morphological operational taxonomic units (mOTUs), 3) random assignment of samples to analysts, 4) post-count identification and documentation of taxa, and 5) increased QC samples. The revised protocol reduced taxonomic bias, as measured by reduction in analyst signal, and improved similarity among QC samples. Reduced taxonomic bias improves the performance of biological assessments, facilitates transparency across studies, and refines estimates of diatom species distributions.

Background Devascularization of the parathyroid glands is generally accepted as the most common mechanism for iatrogenic hypocalcemia, a frequently seen complication of both total and completion thyroidectomy procedures. Much has been written about iatrogenic hypoparathyroidism, but few papers have precisely delineated the arterial supply of the parathyroid glands and the common anatomical variations that may impact parathyroid preservation during thyroid surgery. Methods We offer an illustrated review and discussion of the only two anatomic studies published in the medical literature focusing on parathyroid vasculature. In addition, we examine current techniques of parathyroid identification, preservation, and classification. Findings A surgical technique that preserves the parathyroid arteries is vital to preserving the viability of the parathyroid gland(s) during thyroid surgery. In 1907, Halsted and Evans described a technique of ligating the distal branches of the thyroid arteries beyond the origin of the parathyroid arteries, a technique termed ultra-ligation. In 1982, Flament et al.. reported three distinct anatomical variations of the parathyroid arteries which place the parathyroid blood supply at risk for devascularization during thyroid surgery. Our review also highlights novel techniques that aid surgeons in identification and assessment of the parathyroid glands. Conclusions Recognition of the variations of parathyroid anatomy and their potential to lead to devascularization aids thyroid surgeons in their pursuit of parathyroid preservation. An awareness of the variety of novel parathyroid identification and preservation techniques can assist surgeons to achieve this goal.

Extraskeletal Ewing sarcoma (EES) is a rare soft tissue tumor, and EES of the head and neck is particularly rare. Radiographic imaging of these lesions is crucial given their anatomical complexity and infrequent incidence. Conventional EES imaging features include a large, hyperintense, heterogeneously enhancing lesion, with frequent invasion of local structures. In this case report, a 19-year old male presented with left facial swelling and pain. He underwent sclerotherapy and bleomycin treatment for a presumed lymphatic malformation. Initial imaging demonstrated a rim-enhancing lesion within the left buccal space with no muscle invasion or bony erosion present. Two years later, imaging identified an enlarging buccal mass with destruction of the zygomatic arch and inferolateral orbital wall. The patient underwent surgical resection of the mass. Pathology confirmed the mass to be a small round blue cell tumor and FISH testing confirmed the presence of the EWSR1 gene arrangement that is consistent with EES. The patient tolerated the procedure well and underwent chemoradiation therapy. At three years postoperatively, the patient remains disease free. The presented case demonstrates an unusual presentation of a buccal space EES as a rim-enhancing, centrally hypointense mass with no bony erosion or muscular invasion. The location and atypical imaging appearance of this case offer insight for future diagnosis of EES.

Diatom data have been collected in large-scale biological assessments in the United States, such as the U.S. Environmental Protection Agency's National Rivers and Streams Assessment (NRSA). However, the effectiveness of diatoms as indicators may suffer if inconsistent taxon identifications across different analysts obscure the relationships between assemblage composition and environmental variables. To reduce these inconsistencies, we harmonized the 2008-2009 NRSA data from nine analysts by updating names to current synonyms and by statistically identifying taxa with high analyst signal (taxa with more variation in relative abundance explained by the analyst factor, relative to environmental variables). We then screened a subset of samples with QA/QC data and combined taxa with mismatching identifications by the primary and secondary analysts. When these combined "slash groups" did not reduce analyst signal, we elevated taxa to the genus level or omitted taxa in difficult species complexes. We examined the variation explained by analyst in the original and revised datasets. Further, we examined how revising the datasets to reduce analyst signal can reduce inconsistency, thereby uncovering the variation in assemblage composition explained by total phosphorus (TP), an environmental variable of high priority for water managers. To produce a revised dataset with the greatest taxonomic consistency, we ultimately made 124 slash groups, omitted 7 taxa in the small naviculoid (e.g., Sellaphora atomoides) species complex, and elevated Nitzschia, Diploneis, and Tryblionella taxa to the genus level. Relative to the original dataset, the revised dataset had more overlap among samples grouped by analyst in ordination space, less variation explained by the analyst factor, and more than double the variation in assemblage composition explained by TP. Elevating all taxa to the genus level did not eliminate analyst signal completely, and analyst remained the most important predictor for the genera Sellaphora, Mayamaea, and Psammodictyon, indicating that these taxa present the greatest obstacle to consistent identification in this dataset. Although our process did not completely remove analyst signal, this work provides a method to minimize analyst signal and improve detection of diatom association with TP in large datasets involving multiple analysts. Examination of variation in assemblage data explained by analyst and taxonomic harmonization may be necessary steps for improving data quality and the utility of diatoms as indicators of environmental variables.

While deposition of reactive nitrogen (N) in the twentieth century has been strongly linked to changes in diatom assemblages in high-elevation lakes, pronounced and contemporaneous changes in other algal groups suggest additional drivers. We explored the origin and magnitude of changes in two mountain lakes from the end of the Little Ice Age at ca 1850, to ca 2010, using lake sediments. We found dramatic changes in algal community abundance and composition. While diatoms remain the most abundant photosynthetic organisms, concentrations of diatom pigments decreased while pigments representing chlorophytes increased 200–300% since ca 1950 and total algal biomass more than doubled. Some algal changes began ca 1900 but shifts in most sedimentary proxies accelerated ca 1950 commensurate with many human-caused changes to the Earth System. In addition to N deposition, aeolian dust deposition may have contributed phosphorus. Strong increases in summer air and surface water temperatures since 1983 have direct and indirect consequences for high-elevation ecosystems. Such warming could have directly enhanced nutrient use and primary production. Indirect consequences of warming include enhanced leaching of nutrients from geologic and cryosphere sources, particularly as glaciers ablate. While we infer causal mechanisms, changes in primary producer communities appear to be without historical precedent and are commensurate with the post-1950 acceleration of global change.

We observed four Gomphonema taxa with a high abundance of Janus cells, which are cells that have valves of two different morphologies, also termed heterovalvar cells. The specimens were collected from a habitat with periodic drying, alternating with standing water. A high proportion of Gomphonema Janus cells (up to 20% of the frustules for each taxon) were found. Heterovalvy within a frustule is based on stria count, and two types of heterovalvy were observed. Cells produced either coarsely or finely striated valves with discontinuous phenotypic plasticity or highly variable stria density within a frustule along a continuous phenotypic gradient. In our study, we measured stria density in complete frustules and single valves. Other features of the frustules showed no noticeable variation. Variable stria density was found in frustules and single valves, although it is not possible to determine whether the single valves were part of Janus cells or homomorphic frustules. Therefore, our conclusions are based o...

Iran is a large country with a great diversity of aquatic ecosystems including rivers, springs, shallow seas, lakes, waterfalls, lagoons, and wetlands. Despite the many types of aquatic habitats, there has been a limited study of the diatom flora. The purpose of this study is to present the diatom species and characterize their distribution in the Karaj River, which flows in Iran’s Central Alborz region. The Alborz is one of the Irano-Anatolian ecoregions that serve as biodiversity hotspots. The Central Alborz, located in the middle part of this mountainous area, is an outstanding ecological and geological resource. This study uses the diatom flora to determine the biodiversity in one of the major rivers of the Central Alborz. Periphytic diatom samples were collected monthly from six stations along the length of the Karaj River between May 2011 and April 2012. A total of 128 diatom taxa was found from 48 genera expanding our understanding of regional aquatic diversity as 42 species are recorded as new for the diatom flora of Iran. Furthermore, the biogeography of the diatom flora of the Karaj River is considered in relation to the rest of Iran, the Middle East, and Asian and European diatom communities. © 2019, © 2019 The International Society for Diatom Research.

We present the case of a 38-year-old Caucasian female who underwent a total thyroidectomy for papillary thyroid carcinoma. We identified a large anomalous superior thyroid artery (STA) that emerged as a second branch of the external carotid artery and entered the thyroid isthmus superficial to the right sternothyroid muscle. In this case report, we discuss the embryology of the thyroid gland as well as the possible embryological basis for this unusual course of the STA. In doing so, we aim to improve recognition of the potential vascular variations in the thyroid gland, in turn aiding surgeons in the prevention of unnecessary complications and providing insight into the embryologic development of this organ.

Background Pharyngoesophageal stenosis (PES) is a serious complication that substantially impacts functional outcomes and quality of life (QOL) for up to a third of head and neck cancer patients who undergo radiotherapy. Dysphagia is often multifactorial in nature and is a devastating complication of treatment that impacts patients' QOL, general health and overall wellbeing. The authors detail the clinical presentation, risk factors, imaging characteristics, preventive measures, and multimodality treatment options for PES. Methods The authors present a comprehensive management algorithm for PES, including treatment by dilation, stenting, spray cryotherapy and dilation, and reconstructive treatment options utilizing different pedicled and free flaps. Results The authors advocate for a thorough assessment of the extent and degree of pharyngoesophageal involvement of PES to determine the optimal management strategy. Conclusions The development of post treatment dysphagia requires appropriate imaging and biopsy, when indicated, to rule out the presence of persistent/recurrent cancer. Multidisciplinary management by a team of physicians well-versed in the range of diagnostic and therapeutic interventions available for PES is critical to its successful management.

Didymosphenia geminata has received a great deal of attention in the last 25 years, and considerable effort has gone into determining the origin, ecological impact, and economic consequences of its invasive behavior. While environmental conditions are a controlling influence in distribution, the extreme success of the species may be tied to its basic biology and life history. Little is known, however, about population dynamics, size restoration and reproduction of D. geminata. The objective of this study was to determine the temporal patterns in cell size frequency, size restoration strategy, and synchronization of life cycles between populations in close proximity. We implemented FlowCam technology to measure the length of more than 100,000 D. geminata cells from two sites in South Boulder Creek, Colorado over 1 year. We applied finite mixture modeling to uncover temporal patterns in size distribution. Our results show that collections of D. geminata exhibited a complex, multimodal size distribution, almost always containing four overlapping age cohorts. We failed to observe direct visual evidence of the sexual phase. Multiple abrupt and directional shifts in size distribution, however, were documented providing conclusive evidence of cell size restoration. Lastly, nodules in close proximity were asynchronous with respect to size frequency profiles and size diminution, highlighting the relevance of spatial heterogeneity in in situ diatom size dynamics. This study is the first to document the complexity of diatom cell size distribution in a lotic system, size restoration in D. geminata, and the variability in rates of size reduction at microhabitat spatial scales.

Objective: To assess the relationship between ADHD and performance of household chores. Method: A 72-question online questionnaire was developed to collect demographic/clinical information as well as parents’ assessment of their child’s performance of self-care (SC) and family-care (FC) chores. Results: The sample consists of 797 primary caregivers of children with ADHD. The overwhelming majority of parents believed that ADHD to some extent affected their child’s ability to independently and satisfactorily complete SC and FC chores. An inverse relationship was noted between parent ratings of a child’s ability to do chores independently and satisfactorily and the likelihood they believed ADHD affected chore performance. There was no difference in chore performance between children with or without co-morbid oppositional defiant disorder. Conclusion: Given that household routines, including chores, play an important role in children’s development and psychosocial adjustment, clinicians must be sensitive to the adverse impact that ADHD may have in this regard.

Multifocal cystic oncocytosis (MCO) is a rare, benign process accounting for approximately 0.1% of salivary gland lesions. Salivary oncocytosis is characterized by multiple unencapsulated solid nodules of oncocytic cells derived from transformed striated ducts. MCO is a variant of salivary oncocytosis which manifests as cystically dilated striated ducts. It is difficult to obtain a definitive preoperative diagnosis of MCO; therefore, these lesions are commonly treated with surgery. We report the unique case of a 66-year-old male who previously underwent a superficial left parotidectomy for a pleomorphic adenoma. Four years later, he presented with clinical and radiographic suspicion of a multifocal recurrent pleomorphic adenoma. The patient subsequently underwent a revision parotidectomy. However, final pathology confirmed a diagnosis of MCO. Although MCO is commonly treated with surgery due to lack of a definitive preoperative diagnosis, surgery is unnecessary outside of diagnostic, functional or cosmetic considerations. Thus, if a patient with parotid oncocytosis treated by superficial parotidectomy develops disease re-manifestation in the residual deep lobe, further surgery is not indicated. There is no risk of malignant progression in this process. We report on this unusual entity as it may mimic salivary malignancy or, as in this case, recurrence of benign disease.

The nuisance species Didymosphenia geminata is thought to have been spread by humans across North and South America and New Zealand. This diatom is of interest for its ability to form thick benthic mats in streams, altering ecosystem properties. Little is known, however, about its historic distribution and the parameters that are associated with its growth in absence of human influence. Although it is considered to be native to Arctic regions, its status at lower latitudes is uncertain. We measured the concentration of D. geminata cells in a sediment core from Beauty Lake, WY, a record that dates back to the Late Pleistocene. From approximately 11,233–8750 years before present (ybp), a Didymosphenia maximum persisted, with peak concentrations of 3774±20 valves/mg dry sediment (9985 ybp). The period corresponded to low flux of Al, Fe, and P within the sediments, supporting the importance of low P in controlling distribution. Furthermore, we demonstrate that D. geminata arrived in Beauty Lake shortly after deglaciation of the watershed. This species arrived without the aid of human introduction, implying an inherent ability for dispersal. We also examined the sediment record of nearby Yellowstone Lake, WY for the presence of D. geminata during the same time interval, but cells were not detected. The Yellowstone caldera is composed of rhyolite, a rock rich in silica (Si) and modest amounts of P. We conclude that both watersheds were exposed to the potential colonization by D. geminata, but just as the North Island of New Zealand has not been able to support this diatom because of P concentrations exceeding a threshold, the Yellowstone watershed is not able to support it either.

Typical surgical treatment for invasive thyroid carcinoma at the level of the cricoid substantially reduces surrounding cartilaginous support and risks damage to the recurrent laryngeal nerve (RLN). We present a novel tracheal reconstructive technique that minimizes this injury risk. A 72-year-old man with recurrent invasive thyroid carcinoma underwent cricotracheal resection and reconstruction using a stair-step approach. Diseased cartilage was removed by a left hemitracheal and hemicricoid resection. A portion of normal trachea was also resected on the contralateral right side, removing the third and fourth hemitracheal rings, to close the defect with a sliding tracheoplasty and avoid dissection near the right cricothyroid joint on the side of the functioning RLN. The trachea was elevated superiorly and reanastomosed to the cut margin of the cricoid. This novel stair-step approach to tracheal reconstruction offers reduced risk of injury to the contralateral RLN while still establishing a patent airway.

Pharyngoesophageal stenosis (PES) is a common and serious complication of head and neck cancer treatments such as radiation therapy, chemotherapy, tracheoesophageal puncture placement, and total laryngectomy surgery. Dilation-resistant stenosis requires surgical reconstruction, often with a radial forearm free flap (RFFF). With the present technique, the authors refine their previous bipaddled free flap design used to reconstruct a persistent tracheoesophageal fistulae (TEF) in combination with PES. Accordingly, we present a novel bipaddled triangular RFFF design ideally suited to address the shape of the defect in the posterior tracheal wall that results when the TEF is opened and the esophageal and tracheal components are restored.

Background Reconstruction of orbit-sparing palatomaxillary defects requires consideration of globe dystopia, orbital volume, eyelid position and function, and the nasolacrimal system to preserve and optimize vision, globe protection, and appearance. We describe the fundamentals of orbital and eyelid anatomy, common orbital complications related to palatomaxillary reconstruction, and preemptive and corrective surgical techniques to be utilized during and after globe-sparing palatomaxillary reconstruction. Methods We present a review of the literature supplemented by clinical case examples. Results We advocate for the use of preemptive and corrective techniques to ensure optimal aesthetic and functional outcomes for patients with orbital defects. Conclusions Recognition and anticipation of problems in patients undergoing midface ablative and reconstructive procedures are vital to the implementation of corrective measures. Incision choice, orbital volume restoration, appropriate orbital floor reconstruction, and permanent or temporary lower eyelid suspension during the primary surgery can all significantly impact the development of long-term orbital complications.

The Biological Condition Gradient (BCG) is a conceptual model that describes changes in aquatic communities under increasing levels of anthropogenic stress. The BCG helps decision-makers connect narrative water quality goals (e.g., maintenance of natural structure and function) to quantitative measures of ecological condition by linking index thresholds based on statistical distributions (e.g., percentiles of reference distributions) to expert descriptions of changes in biological condition along disturbance gradients. As a result, the BCG may be more meaningful to managers and the public than indices alone. To develop a BCG model, biological response to stress is divided into 6 levels of condition, represented as changes in biological structure (abundance and diversity of pollution sensitive versus tolerant taxa) and function. We developed benthic macroinvertebrate (BMI) and algal BCG models for California perennial wadeable streams to support interpretation of percentiles of reference-based thresholds for bioassessment indices (i.e., the California Stream Condition Index [CSCI] for BMI and the Algal Stream Condition Index [ASCI] for diatoms and soft-bodied algae). Two panels (one of BMI ecologists and the other of algal ecologists) each calibrated a general BCG model to California wadeable streams by first assigning taxa to specific tolerance and sensitivity attributes, and then independently assigning test samples (264 BMI and 248 algae samples) to BCG Levels 1–6. Consensus on the assignments was developed within each assemblage panel using a modified Delphi method. Panels then developed detailed narratives of changes in BMI and algal taxa that correspond to the 6 BCG levels. Consensus among experts was high, with 81% and 82% expert agreement within 0.5 units of assigned BCG level for BMIs and algae, respectively. According to both BCG models, the 10th percentiles index scores at reference sites corresponded to a BCG Level 3, suggesting that this type of threshold would protect against moderate changes in structure and function while allowing loss of some sensitive taxa. The BCG provides a framework to interpret changes in aquatic biological condition along a gradient of stress. The resulting relationship between index scores and BCG levels and narratives can help decision-makers select thresholds and communicate how these values protect aquatic life use goals.

Clay settling areas are large impoundments brought about by phosphate mining with water-holding capacity that renders it very poor for agriculture and crop production. This study aims to enhance water percolation in phosphatic clay using porous diatom frustules under laboratory conditions. Phosphatic clay collected from settling areas was brought to the laboratory for the experiment. Diatom frustules were purchased commercially and dry samples of the diatom,Didymospheniawere provided by the University of Colorado-Boulder. Oven-dried clay was mixed with diatom frustules into 125 mL centrifuge tubes following a 1:1 volume ratio as experimental set-ups while pure phosphatic clay was used as control. Deionized water was poured into each set-up and the percentage of unpercolated water overlying the sediment, water retained in the sediment particles, water that percolated and passed through the hole of the centrifuge tube were monitored for 48 hours. Results showed that the addition of diatom frustules enhances the percolation of water in the sediment mixture especially those withDidymospheniafrustules. However, this mixture also showed higher percentage of water retained in the sediment particles which could be attributed to the high carbon and organic content brought about by the presence of stalks which is a major component of this species morphology. Considering howDidymospheniadisturbs freshwater habitats, proper management may render it useful for the mitigation of clay settling areas in the land environment. The implication of this on crop production remains to be explored and furtherin situexperimentations need to be conducted.IMPORTANCEClay settling areas abound in places where phosphate mining is conducted. The very fine particles and the chemical property of this phosphatic clay allows it to hold water more than normal clay sediments making the area unstable and less suitable for agricultural use. Studies show that mitigative measures to enhance surface drainage is very costly leaving most areas barren and unused. Diatoms are unicellular algae in various size and shapes with silicified cell walls that are porous and are ubiquitous in aquatic environments. The significance of our research is being able to demonstrate the potential use of diatoms, most especially the genusDidymospheniawhich is regarded as an environmental threat to some habitats, in mitigating the drainage problem in clay settling areas by mixing phosphatic clay with diatom frustules. This process is cost-effective and more importantly provides utilization of a resource that is regarded as nuisance in freshwater environments.

Microbial life flourishes in the ponds of the McMurdo Sound Region, which includes the McMurdo Dry Valleys (MDV) and the exposed coastal areas of Ross Island, Antarctica. Diatoms live within resident microbial mats, and because of the simplified trophic structure and limited dispersal vectors, the McMurdo Sound Region is an ideal locality to investigate diatom community assembly processes. Wind is hypothesized to transport microbiota between habitats, and following the species-sorting perspective, local conditions should act as an environmental filter. However, the role of spatial scale versus habitat characteristics on diatom community structure has not been investigated. To gain insight into these processes, we sampled microbial mats from 25 ponds and used variation partitioning to assess the spatial scales at which diatoms were influenced by chemistry and physical variables. We found substantial spatial structure in diatom communities, and spatial scale explained more variability than environmental variables. No diatoms were exclusive to Ross Island, but some species were only found in the MDVs. Furthermore, diatom communities were more likely to resemble those from other nearby ponds rather than distant ones, regardless of environmental conditions. Of the environmental variables, bromide and chloride (both indicators of marine influence) were among the most important. These results suggest that geography, dispersal, and historical environmental conditions play a major role in structuring diatom communities at large spatial scales, and chemistry may be more important within regions. These results help explain the biogeography of diatoms here and elsewhere and expand our knowledge of mechanisms influencing microbial metacommunity structure.

Reactive nitrogen (Nr) from anthropogenic sources has been altering ecosystem function in lakes of the Rocky Mountains, other regions of western North America, and the Arctic over recent decades. The response of biota in shallow lakes to atmospheric deposition of Nr, however, has not been considered. Benthic algae are dominant in shallow, high- elevation lakes and are less sensitive to nutrient inputs than planktonic algae. Because the benthic substrate is typically more nutrient rich than the water column, shallow lakes are not expected to show evidence of anthropogenic Nr. In this study, we assessed sedimen- tary evidence for regional Nr deposition, sediment chronology, and the nature of algal community response in five shallow, high-elevation lakes in Grand Teton National Park (GRTE). Over 140 diatom taxa were identified from the sediments, with a relatively high species richness of taxa characteristic of oligotrophic conditions. The diatom assemblages were dominated by benthic taxa, especially motile taxa. The GRTE lakes demonstrate assemblage-wide shifts in diatoms, including the following: (1) synchronous and signifi - cant assemblage changes centered on ca. A.D. 1960; (2) pre-1960 assemblages differed significantly from post-1960 assemblages; (3) pre-1960 diatom assemblages fluctuated randomly, whereas post-1960 assemblages showed directional change; and (4) changes in δ 15 N signatures were correlated with diatom community composition. These results demonstrate recent changes in shallow high-elevation lakes that are most correlated with anthropogenic Nr. It is also possible, however, that the combined effect of Nr deposition and warming is accelerating species shifts in benthic diatoms. While uncertainties remain about the potential synergy of Nr deposition and warming, this study adds shallow lakes to the growing list of impacted high-elevation localities in western North America.

Algal blooms caused by the stalk-forming diatom Didymosphenia geminata impact the habitat structure and functioning of stream ecosystems. We evaluated site-specific geomorphic controls on D. geminata in a cobble bed river in the Front Range of the Rocky Mountains. Entrainment potential, defined as the ratio of mean bed shear stress to the critical shear stress, was found to be the most important control on total abundance. A comparison with critical thresholds for sediment transport showed that the requirements for flushing flows to control D. geminata blooms are similar to that required for channel maintenance. Environmental parameters influencing the morphology of the algal mats and the potential for D. geminata to dominate the benthic algal community were also investigated. The results not only contribute to understanding of the controls on benthic algal growth in dynamic streams but also for management of water releases as mitigation for the control of future blooms of D. geminata.

The environmental health of aquatic ecosystems is critical to society, yet traditional assessments of water quality have limited utility for some bodies of water such as large rivers. Sequencing of environmental DNA (eDNA) has the potential to complement if not replace traditional sampling of biotic assemblages for the purposes of reconstructing aquatic assemblages and, by proxy, assessing water quality. Despite this potential, there has been little testing of the ability of eDNA to reconstruct assemblages and their absolute and relative utility to infer water quality metrics. Here, we reconstruct phytoplankton communities by amplifying and sequencing DNA from a portion of the 23S rRNA region from filtered water samples along a 2900-km transect in the Mississippi River. Across the entire length, diatoms dominated the assemblage (72.6%) followed by cryptophytes (8.7%) and cyanobacteria (7.0%). There were no general trends in the abundances of these major taxa along the length of the river, but individual taxon abundance peaked in different regions. For example, the abundance of taxa genetically similar to Melosira tropica peaked at approximately 60% of all reads 2750 km upstream from the Gulf of Mexico, while taxa similar to Skeletonema marinoi began to increase below the confluence with the Missouri River until it reached approximately 30% of the reads at the Gulf of Mexico. There were four main clusters of samples based on phytoplankton abundance, two above the confluence with the Missouri and two below. Phytoplankton abundance was a poor predictor of NH4+ concentrations in the water, but predicted 61% and 80% of the variation in observed NO3-and PO43-concentrations, respectively. Phytoplankton richness increased with increasing distance along the river, but was best explained by phosphate concentrations and water clarity. Along the Mississippi transect, there was similar structure to phytoplankton and bacterial assemblages, indicating that the two sets of organisms are responding to similar environmental factors. In all, the research here demonstrates the potential utility of metabarcoding for reconstructing aquatic assemblages, which might aid in conducting water quality assessments.

Background Medullary thyroid carcinoma (MTC) is a somewhat rare, particularly aggressive form of thyroid cancer. The authors present what we believe to be the first case of MTC diagnosed solely on the basis of molecular testing, as well as a review of the literature concerning this topic and oncocytic variants of MTC. Case description A 30-year-old female patient with a 1.1 cm thyroid nodule underwent a fine-needle aspiration biopsy showing a Bethesda IV Hurthle cell neoplasm. Molecular testing of the specimen identified a RET M918 T mutation. The patient underwent a total thyroidectomy and bilateral central neck dissection. Initial pathologic analysis yielded a diagnosis of Hurthle cell adenoma. Based on the patient's known RET mutation, immunohistochemistry for calcitonin was performed and yielded a positive result. The final diagnosis was amended to an oncocytic variant of medullary thyroid carcinoma. Discussion Had this patient undergone fine-needle aspiration (FNA) biopsy without molecular testing or serum calcitonin measurement, the patient's disease would have been diagnosed as a Hurthle cell adenoma. Despite the lack of characteristic features of malignancy and the rarity of oncocytic MTC, the diagnostic pitfall in this oncocytic lesion was avoided due to molecular testing at the time of FNA biopsy. Conclusion This case draws attention to the unique clinical value of molecular testing in the diagnosis of MTC. The authors believe this case supports the consideration for molecular testing to prevent missed diagnoses in cases of rare benign-appearing disease.

Sources of seismic hazard in the Puget Sound region of northwestern Washington include deep earthquakes associated with the Cascadia subduction zone, and shallow earthquakes associated with some of the numerous crustal (upper-plate) faults that crisscross the region. Our paleoseismic investigations on one of the more prominent crustal faults, the Darrington–Devils Mountain fault zone, included trenching of fault scarps developed on latest Pleistocene glacial sediments and analysis of cores from an adjacent wetland near Lake Creek, 14 km southeast of Mount Vernon, Washington. Trench excavations revealed evidence of a single earthquake, radiocarbon dated to ca. 2 ka, but extensive burrowing and root mixing of sediments within 50–100 cm of the ground surface may have destroyed evidence of other earthquakes. Cores in a small wetland adjacent to our trench site provided stratigraphic evidence (formation of a laterally extensive, prograding wedge of hillslope colluvium) of an earthquake ca. 2 ka, which we interpret to be the same earthquake documented in the trenches. A similar colluvial wedge lower in the wetland section provides possible evidence for a second earthquake dated to ca. 8 ka. Three-dimensional trenching techniques revealed evidence for 2.2 ± 1.1 m of right-lateral offset of a glacial outwash channel margin, and 45–70 cm of north-side-up vertical separation across the fault zone. These offsets indicate a net slip vector of 2.3 ± 1.1 m, plunging 14° west on a 286°-striking, 90°-dipping fault plane. The dominant right-lateral sense of slip is supported by the presence of numerous Riedel R shears preserved in two of our trenches, and probable right-lateral offset of a distinctive bedrock fault zone in a third trench. Holocene north-side-up, right-lateral oblique slip is opposite the south-side-up, left-lateral oblique sense of slip inferred from geologic mapping of Eocene and older rocks along the fault zone. The cause of this slip reversal is unknown but may be related to clockwise rotation of the Darrington–Devils Mountain fault zone into a position more favorable to right-lateral slip in the modern N-S compressional stress field.

We reconstructed the phylogeny of representatives from nine genera and three families of the Cymbellales using two nuclear and three chloroplast genes. After rooting with Anomoeoneis, Placoneis was...

Alpine lakes receive a large fraction of their nutrients from atmospheric sources and are consequently sensitive to variations in both the amount and chemistry of atmospheric deposition. In this study we explored the spatial changes in lake water chemistry and biology along a gradient of dust deposition in the Wind River Range, Wyoming. Regional differences were explored using the variation in bulk deposition, lake water, sediment, and bedrock geochemistry and catchment characteristics. Dust deposition rates in the Southwestern region averaged 3.34 g m -2 year -1 , approximately three times higher than deposition rates in the North- western region (average 1.06 g m -2 year -1 ). Dust-P deposition rates ranged from 87 l gPm 2 day -1 in the Northwestern region to 276 l gP m 2 day -1 in the Southwestern region. Subalpine and alpine lakes in the Southwestern region had greater total phosphorus (TP) concentrations (5-13 l gL -1 ) and greater sediment phosphorus (SP) concentrations (2-5 mg g -1 ) than similar lakes elsewhere in the region (1-8 l gL -1 TP, 0.5-2 mg g -1 SP). Lake phosphorus concentrations were related to dissolved organic carbon (DOC) across vegetation gradients, but related to the percent of bare rock, catchment area to lake area, and catchment steepness across dust deposition gradients. Modern phytoplankton and zooplankton biomasses were two orders of magnitude greater in the Southwest than in the Northwest, and alpine lakes in the Southwest had a unique diatom species assemblage with relatively higher concentrations of Asterionella formosa, Pseudostauros

Size analysis of diatom populations has not been widely considered, but it is a potentially powerful tool for understanding diatom life histories, population dynamics, and phylogenetic relationships. However, measuring cell dimensions on a light microscope is a time-consuming process. An alternative technique has been developed using digital flow cytometry on a FlowCAM® (Fluid Imaging Technologies) to capture hundreds, or even thousands, of images of a chosen taxon from a single sample in a matter of minutes. Up to 30 morphological measures may be quantified through post-processing of the high resolution images. We evaluated FlowCAM size measurements, comparing them against measurements from a light microscope. We found good agreement between measurement of apical cell length in species with elongated, straight valves, including small Achnanthidium minutissimum (11-21 µm) and large Didymosphenia geminata (87–137 µm) forms. However, a taxon with curved cells, Hannaea baicalensis (37–96 µm), showed differences of ~ 4 µm between the two methods. Discrepancies appear to be influenced by the choice of feret or geodesic measurement for asymmetric cells. We describe the operating conditions necessary for analysis of size distributions and present suggestions for optimal instrument conditions for size analysis of diatom samples using the FlowCAM. The increased speed of data acquisition through use of imaging flow cytometers like the FlowCAM is an essential step for advancing studies of diatom populations.

The ephemeral stream habitats of the McMurdo Dry Valleys of Antarctica support desiccation and freeze-tolerant microbial mats that are hot spots of primary productivity in an otherwise inhospitable environment. The ecological processes that structure bacterial communities in this harsh environment are not known; however, insights from diatom community ecology may prove to be informative. We examined the relationships between diatoms and bacteria at the community and taxon levels. The diversity and community structure of stream microbial mats were characterized using high-throughput pyrosequencing for bacteria and morphological identification for diatoms. We found significant relationships between diatom communities and the communities of cyanobacteria and heterotrophic bacteria, and co-occurrence analysis identified numerous correlations between the relative abundances of individual diatom and bacterial taxa, which may result from species interactions. Additionally, the strength of correlations between heterotrophic bacteria and diatoms varied along a hydrologic gradient, indicating that flow regime may influence the overall community structure. Phylogenetic consistency in the co-occurrence patterns suggests that the associations are ecologically relevant. Despite these community- and taxon-level relationships, diatom and bacterial alpha diversity were inversely correlated, which may highlight a fundamental difference between the processes that influence bacterial and diatom community assembly in these streams. Our results therefore demonstrate that the relationships between diatoms and bacteria are complex and may result from species interactions as well as niche-specific processes.

The diatom Didymosphenia geminata, which forms nuisance blooms in low nutrient streams worldwide, was documented as an aggressive invader in South America in 2010 from the Futaleufu basin (43.2°S), in Chilean and Argentinean Patagonia. Within 1 year it was confirmed from 20 rivers distributed over 800 km. Driven by perceived economic impacts to tourism and recreation, a strong response ensued, with education, monitoring and nascent biosecurity efforts based on similar measures in New Zealand. Considering the difficulty in containment (potential range on New Zealand's South Island was occupied by D. geminata within 3 years), the much larger potential range, and limited resources or previous experience in managing invaders in continental waters in South America, it is unlikely that current biosecurity measures will produce significant results. Lacking a coordinated strategic approach or conservation priorities, existing efforts may divert resources from alternatives with greater potential for success, while potentially feeding the public perception that the problem is being addressed. We propose a conservation strategy based on best available but incomplete information on habitat requirements, and a conceptual model of invasion vectors to identify defensible conservation zones (islands and hydrographically isolated areas) with greater potential for being maintained invasion-free.

Sediment records from several high alpine lakes in the Grand Teton National Park (GRTE), Wyoming were examined for stable isotopic signatures δ15N and diatom community composition because atmospheric deposition of reactive nitrogen (Nr) is known to be altering ecosystem functioning in other lakes of the Rocky Mountain Range. Alpine lakes exposed to greater Nr impacts in Colorado have higher N:P ratios in the water column, indicating an excess of N, thus GRTE sites were selected across a range of N:P values, spanning measures indicative of nitrogen to phosphorus limitation. Sediment cores were analyzed for diatom relative abundances, concentrations of carbon, nitrogen and phosphorus, and stable isotopic signatures of δ13C and δ15N. Every sediment record showed progressive δ15N depletion, evidence of increasing Nr deposition during the past forty years. In the GRTE, benthic flora dominated the community composition without changes to the fossil diatom taxonomy, a response atypical of other Nr impacted sites in the Rocky Mountain Range that have exhibited a marked shift towards nitrophilous planktonic diatoms Asterionella formosa and Fragilaria crotonensis. The suite of GRTE lacustrine sediment records exhibited a continuum of increasing nutrient enrichment from low to high N:P ratios, suggesting that lakes sensitive to Nr enrichment exhibit elevated ratios of N:P. The long-term impact of Nr deposition has not reached a critical threshold, but monitoring of the GRTE lakes needs to incorporate assessment of the N:P ratios in advance of greater ecological impacts.

We observed six diatom taxa from North American samples and one taxon from China that are considered within the genus Encyonema Kutzing. Two of the taxa are described as new, Encyonema reimeri Spaulding, Pool et Castro sp. nov. and Encyonema nicafei Spaulding sp. nov. A third taxon, Encyonema stoermeri Spaulding, Pool et Castro nom. nov., shat. nov. is assigned a new name and rank. In the past, these taxa have been ascribed to several names, but primarily the names Cymbella muelleri Hustedt and C. muelleri f. ventricosa (Tempere et Peragallo) Reimer have been used, based on their inclusion in the two volumes of “The Diatoms of the United States”. We compare the new species with other members of this group of taxa, including Encyonema latum Krammer, E. sinicum Krammer and E. yellowstonianum Krammer. This group of species shares the features of 1) a broad axial area, 2) raphe branches curved with the convex side toward the dorsal valve margin, 3) slightly expanded and dorsally deflected proximal r...

The Reimer Diatom Herbarium (ILH) at Iowa Lakeside Laboratory (ILL), a field station of Iowa's state universities, contains 3,280 permanent diatom slides of collections made from prairie potholes, alkaline fens, acid bogs, eutrophic lakes, saline lakes, Pleistocene paleolakes, and Miocene fossil deposits near ILL. The herbarium has a focus on collections made within Dickinson County, a region with an important legacy of study by students and visiting researchers from the US, Canada, and international institutions. The herbarium is well documented by taxon and location catalogues. The taxon card catalogue contains over 2,800 records referencing 67 genera, and the location card catalogue references collection sites from 51 counties in 16 North American states. Curated slides include over 300 species identifications made, or verified, by C.W. Reimer. Most curated slides have diatom specimens identified to species, circled with a diamond objective marker, and indicated on the slide label. Six holotypes are included in the herbarium and we present the first light micrograph images of these type specimens. We present documentation of the contents and current condition of the herbarium and report that it is now available to researchers for scientific study. Many of the sites represented in the Reimer Diatom Herbarium are the same locations visited each year by students and visiting researchers at ILL, resulting in an important resource for monitoring environmental change, resolving taxonomic issues, and understanding species distributions in unique habitats.