We conclude that the most parsimonious scenario for

estab

We conclude that the most parsimonious scenario for

establishment of pythons in Florida involves the release of a relatively small number of founders prior to 1985. Our results demonstrate that for pythons and other species with low inherent detection probabilities, early action during incipient phases of an invasion is critical and understanding likely introduction scenarios is important for preventing similar situations from occurring elsewhere or with other species.”
“Two new Antillean endemic species, Piper abajoense from Puerto Rico, and Piper claseanum from the Dominican Republic, are described and illustrated. The former species resembles the widely distributed Piper hispidum, including the somewhat scabrous leaf surfaces, typically asymmetric Elafibranor clinical trial leaf bases, PLX4032 molecular weight and the bracts, flowers, and fruits forming distinct bands around the spike, but is distinguished by the combination of glabrous and stylose fruits (vs. densely puberulent and estylose), laterally (vs. apically) dehiscent anthers, and shorter spikes. The latter species resembles Piper samanense, another endemic species from the Dominican

Republic, in vegetative morphology, including the leathery leaves with pellucid dots visible below when dry, but differs in its long-pedicellate flowers and fruits (vs. sessile or pseudo-pedicellate), puberulent rachis and pedicels (vs. densely white-pubescent), and puberulent vs. pubescent fruits. A phylogeny based on the nuclear ribosomal Internal Transcribed Spacer (ITS) and chloroplast intron psbJ-petA indicates proper placement of these two new species within clades Radula and Enckea, respectively. Two keys are provided, one to all species of Piper from Puerto Rico, the other to the palmate-veined species from the Dominican Republic.”
“BACKGROUND: Flat inferior vena cava (IVC) has been associated with shock and mortality in young trauma patients (age smaller than 55 years). Because of the greater possibility of nonhypovolemic shock in the elderly, we hypothesized that there would be no correlation between IVC ratio and the presence of shock. METHODS: We conducted a retrospective

cohort study of all severely injured (Injury Severity Score [ISS] bigger than = Nutlin-3 inhibitor 15), blunt trauma patients 55 years or older from April 2006 to April 2011. Only patients undergoing axial imaging of the IVC within 1 hour of arrival were considered. Anteroposterior and transverse diameter of the IVC were measured 2.5 mm above the renal veins. Transverse-to-anteroposterior IVC ratios of 2, 3, and 4 were analyzed. Hemodynamic (heart rate, blood pressure, systolic blood pressure, shock index, and adjusted shock index [ASI]) and laboratory (hemoglobin, HCO3, base excess) markers of shock were reviewed. Correlation among shock markers, IVC ratio, and death was analyzed using multivariate logistic regression. Relationship between shock and IVC ratio was analyzed using logistic regression and chi(2) where appropriate.

Objective: To determine whether 15 days is a suitable cut-off

\n\nObjective: To determine whether 15 days is a suitable cut-off age for different approaches to the management of infants with fever. selleck screening library Patients and\n\nMethods: Cross-sectional descriptive study of infants. <3 months of age with fever without a source seen between September 1, 2003 and August 30, 2010

in the pediatric emergency department of a tertiary teaching hospital. All infants. <3 months of age with fever without a source (<= 38 degrees C) were included. The following data were collected: age, sex, temperature, diagnosis, management in pediatric emergency department, and outcome.\n\nResults: Data were collected for 1575 infants; of whom, 311 (19.7%, 95% confidence intervals [CI]: 17.7-21.7) were found to have an SBI. The rate of SBI in the patients who were 15 to 21 days of age was 33.3% (95% CI: 23.7%-42.9%), similar to that among infants who were 7 to 14 days of age (31.9%, 95% CI: 21.1%-42.7%) and higher than among those older than 21 days of age (18.3%, 95% CI: 16.3-20.3%).\n\nConclusions: Febrile infants 15 to 21 days of age had a rate of SBI similar to younger infants and higher than older age infants. It is not appropriate

to establish the approach to management of find more infants with fever based on a cut-off age of 2 weeks.”
“Non-invasive imaging techniques for the detection of coronary artery disease (CAD) may have technical problems in patients with atrial fibrillation (AF). Although the prognostic value of exercise

echocardiography (ExEcho) has been well established in several subgroups of patients, it has not yet been specifically evaluated in these patients.\n\nFrom a population of 8095 patients with known or suspected CAD referred for ExEcho, 419 had AF at the time of the tests. Ischaemia was defined as the development of new or worsening wall motion abnormalities with exercise. Endpoints were hard cardiac events (i.e. cardiac death or non-fatal myocardial infarction). Mean age was 68.4 +/- 8.5 years, and 256 patients (61.1%) were men. Ischaemia was detected in 92 patients (22%). Over a mean follow-up of 3.10 +/- 2.98 years, 59 hard cardiac events occurred. The 5-year hard cardiac event rate click here was 37.3% in patients with ischaemia, when compared with 14.5% in patients without ischaemia (P < 0.001). In multivariate analysis, ischaemia on ExEcho remained an independent predictor of hard cardiac events (hazard ratio 1.99, 95% confidence interval 1.06-3.74, P = 0.03), and also provided incremental value over clinical, resting echocardiographic and treadmill exercise data for the prediction of hard cardiac events (P = 0.04).\n\nExEcho provides significant prognostic information for predicting hard cardiac events in patients with AF.

Various forms of recombinant human sCD93 were used to investigate

Various forms of recombinant human sCD93 were used to investigate the effects

of this molecule on both human primarymonocytes and a monocytic cell line, THP-1. We found that sCD93 induced differentiation of monocytes to macrophage-like cells, as evidenced by activated cell adhesion and increased phagocytic activities. In addition, this differentiation resulted in an enhanced https://www.selleckchem.com/products/gkt137831.html response to TLR stimulation in terms of differentiation marker expression and proinflammatory cytokine production. Furthermore, sCD93 enhanced LPS-stimulated TNF-alpha production even prior to monocyte differentiation. To investigate a possible role for sCD93 in the pathogenesis of chronic inflammatory diseases, we assessed the concentration PCI-34051 of sCD93 in synovial fluid from patients with rheumatoid arthritis and found it to be significantly increased compared with synovial fluid from patients with osteoarthritis. Together, these data revealed a function for sCD93 that may have implications in inflammation and inflammatory diseases including rheumatoid arthritis. The Journal of Immunology, 2010, 185: 4921-4927.”
“Infantile hemangiomas (IHs) are common neoplasms composed of

proliferating endothelial-like cells. Despite the relative frequency of IH and the potential severity of complications, there LY2835219 purchase are currently no uniform guidelines for treatment. Although propranolol has rapidly been adopted, there is significant uncertainty and divergence of opinion regarding safety monitoring, dose escalation, and

its use in PHACE syndrome (PHACE = posterior fossa, hemangioma, arterial lesions, cardiac abnormalities, eye abnormalities; a cutaneous neurovascular syndrome characterized by large, segmental hemangiomas of the head and neck along with congenital anomalies of the brain, heart, eyes and/or chest wall). A consensus conference was held on December 9, 2011. The multidisciplinary team reviewed existing data on the pharmacologic properties of propranolol and all published reports pertaining to the use of propranolol in pediatric patients. Workgroups were assigned specific topics to propose protocols on the following subjects: contraindications, special populations, pretreatment evaluation, dose escalation, and monitoring. Consensus protocols were recorded during the meeting and refined after the meeting. When appropriate, protocol clarifications and revision were made and agreed upon by the group via teleconference. Because of the absence of high-quality clinical research data, evidence-based recommendations are not possible at present.

Effect of type and concentration of carbon and nitrogen source on

Effect of type and concentration of carbon and nitrogen source on fermentation kinetic parameters were analyzed using logistic and Luedeking-Piret equations. In submerged batch fermentation, yield of CoQ10 was 12.22 mg/L when 40 g/L glycerol was used and specific P005091 datasheet growth rate (0.056/h) as well as growth associated constant (alpha=0.680 mg/g) were higher as compared to other concentrations. Ammonium nitrate and proteose peptone at 5 (alpha=0.677 mg/g; beta= 0.0072 mg/g center dot h)

and 20 g/L (alpha=0.806 mg/g; beta=0.0074 mg/g center dot h), respectively, were optimal for CoQ10 production. CoQ10 formation observed to be both growth and nongrowth associated. In optimized medium CoQ10 formation increased considerably from 1.91 to 14.12 mg/L.”
“Bovine vaccinia (BV), a zoonosis caused selleck compound by Vaccinia virus (VACV), affects dairy cattle and milkers, causing

economic, veterinary and human health impacts. Despite such impacts, there are no experimental studies about the pathogenesis of BV in cows to assess whether there is a systemic spread of the virus and whether there are different ways of VACV shedding. Trying to answer some of these questions, a study was proposed using experimental inoculation of VACV in cows. All experimentally infected cows developed lesions compatible with VACV infection in cattle. Two of the six animals presented VACV DNA in blood and faecal samples, starting at the 2nd and the 3rd day post-infection (d.p.i.), respectively, and lasting until the 36th d.p.i., in an intermittent way. This study provides new evidence that VACV can be detected www.selleckchem.com/products/gsk2126458.html in blood and faeces of infected cows, suggesting that BV could be a systemic disease, and also bringing new information about the epidemiology and pathogenesis of BV.”
“Background: The functions of palmitate turnover in signal transduction are poorly understood. Results: Inhibiting palmitate turnover on R7BP redistributed R7BP-R7 RGS complexes from the plasma membrane to endomembranes,

dissociated them from GIRK channels, and delayed G(i/o) deactivation and channel closure. Conclusion: Palmitate turnover on R7BP promotes GIRK channel deactivation. Significance: Inhibiting palmitate turnover on R7BP could enhance GIRK activity in neurological disorders. Reversible attachment and removal of palmitate or other long-chain fatty acids on proteins has been hypothesized, like phosphorylation, to control diverse biological processes. Indeed, palmitate turnover regulates Ras trafficking and signaling. Beyond this example, however, the functions of palmitate turnover on specific proteins remain poorly understood. Here, we show that a mechanism regulating G protein-coupled receptor signaling in neuronal cells requires palmitate turnover.

Treatment response was defined as 50% reduction in depressive sym

Treatment response was defined as 50% reduction in depressive symptoms at any point during the 12-week trial. One-hundred-forty-eight gene transcripts were significantly associated (1.2-fold, adjusted p <= 0.01) with response to infliximab and were distinct from placebo responders. Transcripts predictive of infliximab response were associated with gluconeogenesis and cholesterol transport, and were enriched in a network regulated by hepatocyte nuclear factor (HNF)4-alpha, a transcription factor involved in gluconeogenesis and cholesterol and lipid homeostasis.

Of the 148 transcripts differentially expressed at baseline, 48% were significantly regulated over time find more in infliximab

responders, including genes related to gluconeogenesis and the HNF4-alpha network, indicating that these predictive genes were responsive to infliximab. Responders also demonstrated inhibition of genes related to apoptosis through TNF signaling at 6 h and 24 h after infusion. Transcripts down-regulated in responders 2 weeks after infliximab were related to innate immune signaling and nuclear factor-kappa B. Thus, baseline transcriptional signatures reflective of alterations in glucose and lipid metabolism predicted antidepressant PLX4032 inhibitor response to infliximab, and infliximab response involved regulation of metabolic genes and inhibition of genes related to innate immune activation. (C) 2013 Elsevier Inc. All rights reserved.”
“Protein aggregation is of great concern to pharmaceutical formulations and has been implicated in several diseases. We engineered an anti-IL-13 monoclonal antibody CNTO607 for improved solubility. Three structure-based engineering approaches were employed in this study: (i) modifying the isoelectric point (pI), SYN-117 clinical trial (ii) decreasing the overall surface hydrophobicity and (iii) re-introducing an N-linked carbohydrate moiety within a complementarity-determining

region (CDR) sequence. A mutant was identified with a modified pI that had a 2-fold improvement in solubility while retaining the binding affinity to IL-13. Several mutants with decreased overall surface hydrophobicity also showed moderately improved solubility while maintaining a similar antigen affinity. Structural studies combined with mutagenesis data identified an aggregation ‘hot spot’ in heavy-chain CDR3 (H-CDR3) that contains three residues ((99)FHW(100a)). The same residues, however, were found to be essential for high affinity binding to IL-13. On the basis of the spatial proximity and germline sequence, we reintroduced the consensus N-glycosylation site in H-CDR2 which was found in the original antibody, anticipating that the carbohydrate moiety would shield the aggregation ‘hot spot’ in H-CDR3 while not interfering with antigen binding.

The high-order flexural vibration modes are

recent advanc

The high-order flexural vibration modes are

recent advancement of AFM dynamic force modes. AFM optical lever detection sensitivity plays a major role in dynamic force modes because it determines the accuracy in mapping surface morphology, distinguishing various tip-surface interactions, and measuring the strength of the tip-surface interactions. In this work, we have analyzed optimization and calibration of the optical lever detection sensitivity for an AFM cantilever-tip ensemble vibrating in high-order flexural modes and simultaneously experiencing a wide range and variety of tip-sample interactions. It is GSK1210151A found that the optimal detection sensitivity depends on the vibration mode, the ratio of the force constant of tip-sample interactions to the cantilever stiffness, as well as the incident laser spot size and its location on the cantilever. It is also found that the optimal detection sensitivity is less dependent on the strength of tip-sample interactions for high-order flexural modes relative to the fundamental mode, i.e., tapping mode. When the force constant of tip-sample interactions significantly exceeds the cantilever stiffness, the optimal detection sensitivity occurs only when the laser spot locates at a certain distance from the cantilever-tip end. Thus, in addition to the “globally optimized detection sensitivity,”

the “tip optimized detection sensitivity” is also determined. P505-15 Finally, we have proposed a calibration method to determine the actual AFM detection sensitivity in high-order flexural vibration modes against the static end-load sensitivity that is obtained traditionally by measuring a force-distance curve on a hard substrate in the contact mode.”
“Cephaloceles are rare neural tube defects. In this study, we retrospectively reviewed the charts of all patients with cephaloceles who underwent surgical treatment in our institute for a 14-year period, between January 1995 and January 2009. There were 27 children (11 boys and 16 girls; mean age, 7.5 mo; range, 1 d to 7 y). Seventeen encephaloceles were occipital; 5, parietal; 2, ethmoidal; 1, frontoethmoidal; 1, nasoethmoidal; and 1, sphenoethmoidal.

The mean size of sac was 3 cm, although 2 cases of giant occipital encephaloceles were observed. this website In 19 cases (70%), the sac contained gliotic brain (encephaloceles) that was excised. All patients were operated on in 1 surgical procedure. Hydrocephalus was found in 16 patients and treated with a ventriculoperitoneal shunt insertion. Postoperatively, there was no neurologic deficit or death. After a mean follow-up period of 7.2 years (range, 6 mo to 11.5 y), all patients were in good condition. In conclusion, occipital cephaloceles are more frequently encountered and are usually associated with hydrocephalus. Surgery should be performed as early as possible and only after careful preoperative planning especially for the anterior cephaloceles.

The 3-year local progression-free survival for those who received

The 3-year local progression-free survival for those who received a high single-dose (24 Gy; n = 45), a low single-dose (<24 Gy; n = 14), or hypofractionation regimens (n = 46) was 88%, 21%, and 17%, respectively (high single dose vs. low single dose, p = .001; high single dose vs. hypofractionation, p < .001). Multivariate analysis revealed the following variables were significant B-Raf inhibitor drug predictors of improved local progression-free survival: 24 Gy dose compared with a lower dose (p = .009) and a single dose vs. hypofractionation

(p = .008).\n\nConclusion: High single-dose, image-guided, intensity-modulated radiotherapy is a noninvasive procedure resulting in high probability of local tumor control for metastatic renal cell cancer generally considered radioresistant according to the classic radiobiologic ranking. (C) 2012 Elsevier Inc.”
“Background: Diffuse large B-cell non-Hodgkin lymphoma (DLBCL) outcome in the United States has not been reported outside the context of clinical trials. Patients and Methods: We reviewed the Surveillance, Epidemiology,;and End Results (SEER) registry and compared survival trends among DLBCL patients from 1973 to 2004. Results: We identified 59,728 patients (mean age, 63 years; 54.4% men, 86.7% Selleckchem Pinometostat white) and had staging information

for 57%, including 30% early-stage (I/II) and 27% advanced-stage (III/IV). Median overall survival (OS) from 1973 to 1979, 1980 to 1989,1990 to 1999, and 2000 to 2004 was 15, 18, 20, and 47 months, respectively (P < .005). For the period from 2000 to 2004, 4-year OS was 46%. Outcome was better in white patients than Geneticin molecular weight in black (47 months versus 29 months) (P=.001). Median OS for patients younger than 60 years old was not reached versus 23 months for patients older than 60 years. Conclusion: The outcome of DLBCL in the United States has improved significantly in the era of monoclonal antibodies; however, racial disparities remain.”
“Background: RNA ligases are essential reagents for many methods in molecular biology including NextGen RNA

sequencing. To prevent ligation of RNA to itself, ATP independent mutant ligases, defective in self-adenylation, are often used in combination with activated pre-adenylated linkers. It is important that these ligases not have de-adenylation activity, which can result in activation of RNA and formation of background ligation products. An additional useful feature is for the ligase to be active at elevated temperatures. This has the advantage or reducing preferences caused by structures of single-stranded substrates and linkers.\n\nResults: To create an RNA ligase with these desirable properties we performed mutational analysis of the archaeal thermophilic RNA ligase from Methanobacterium thermoautotrophicum. We identified amino acids essential for ATP binding and reactivity but dispensable for phosphodiester bond formation with 5′ pre-adenylated donor substrate.

(C) 2012 British Association of Plastic, Reconstructive and Aesth

(C) 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.”
“Persisting Symptoms after Elective Sigmoid Resection for Sigmoid Diverticulitis\n\nIn the past, sigmoid resection in patients with recurrent sigmoid diverticulitis was typically recommended after the second episode. In recent years, this practice has been questioned as well as abandoned in favor of a more individual decision making. After elective sigmoid resection for diverticulitis, however, approximately a quarter of all patients report persistent or new-onset symptoms. In the minority of cases, Small molecule library actually genuine recurrent diverticulitis plays a role,

in which the height of the anastomosis is a determining factor. Often patients report about symptoms suggestive of irritable bowel syndrome, and studies in the recent years also show an overlap of

irritable bowel syndrome and diverticular disease. Recent studies suggest that visceral hypersensitivity and markers https://www.selleckchem.com/products/ldn193189.html of inflammation are correlated in patients with symptomatic diverticular disease. In conjunction with predisposing factors such as obesity, these conditions may be a key reason for persistent complaints. Therefore, on the one hand, it will be up to the physician to identify those patients who are at high risk for complications and have a high probability of remaining symptom-free postoperatively. On the other hand, patients who will SB203580 most likely not benefit from surgery should be directed towards other treatment modalities.”
“Background: Bovine cutaneous fibropapillomas are benign hyperproliferative lesions induced by Bovine Papillomaviruses (BPVs). Bcl-2 is an important anti-apoptotic protein which is expressed in several cancer types. In contrary, p53 is a tumour suppressor protein that mediates cell cycle arrest, apoptosis and senescence in response to cellular stresses. Findings: Here, we investigated immunohistochemically and biochemically, the expression

of bcl-2 and p53 in a subset of BPV positive fibropapillomas and bovine normal skin. Normal skin samples showed a weak signal for both proteins in the cytoplasm of the basal cells. Nine out of twelve (75%) tumour samples stained positive for bcl-2 throughout basal and parabasal layers, with most of cells showing strong cytoplasmic immunoreactivity. Nine out of twelve (75%) fibropapillomas were found to be positive for p53 expression, showing a strong cytoplasmic and perinuclear staining of p53 protein mainly in the basal and parabasal layers. Conclusions: Our data reveal an altered bcl-2 and p53 immunoreactivity in bovine cutaneous fibropapillomas, suggesting involvement of these two proteins in the cutaneous neoplastic transformation through an impaired apoptotic process.”
“Aim This study aimed to compare the effect of extended margin and conventional bleaching trays on tooth bleaching and tooth sensitivity.

Distribution of the patients according to BMI scores was found to

Distribution of the patients according to BMI scores was found to represent the BMI distribution of the Turkish population.\n\nPulmonary and infective complications were significantly higher in EOG patients compared to NRG based on crude confidence interval. Based on adjusted multiple logistic regression analysis, by adjusting the effects of age, sex, comorbidities (diabetes mellitus, hypertension, hyperlipidemia, chronic obstructive pulmonary disease), Mizoribine inhibitor and smoking, the incidence of pulmonary and gastrointestinal complications in EOG was higher compared to NRG. Discharge with morbidity

was significantly higher in OG and EOG compared to NRG.\n\nWe found that obesity does not increase short-term mortality for open heart surgery; however, it increases the risk of postoperative pulmonary and gastrointestinal complications and discharge with morbidity.”
“Colloidal waveguide fabrication based on the convective assisted capillary force assembly technique and their optical properties is presented in this work. A large variety in shape of colloidal check details waveguides is built with their own integrated local light sources. It is highlighted that these structures exhibit propagation of the visible light at the micrometric scale. Finally, the onset of the integration

of a colloidal emitter on a classical photonic system is developed using a stamping method. (C) 2010 American Vacuum Society. [DOI:10.1116/1.3503897]“
“In a previous work [1], the treatment of dye solutions containing Remazol Red BR (RRB) and Novacron Blue C-D (NB) by anodic oxidation using boron doped diamond anode (BDD) demonstrated that the electrochemical treatment is

an efficient alternative for removing color and chemical oxygen demand (COD) and this technology can be used for depuration of real effluents. More recently, these assumptions have been confirmed by oxidizing electrochemically a real textile effluent using BDD anode [2]. Then, as a further development of the research carried out in these previous studies [1,2], in the present work, it has been considered A-1210477 appropriate to extend the investigation to the anodic oxidation, using BDD anode, of a specific real effluent discharged by Brazilian textile industry, adding Na2SO4 or NaCl salts in order to verify the applicability of this treatment producing in situ strong oxidant species (peroxodisulfates or active chlorine, respectively).\n\nIn this study, we also attempt to discuss critical evidence about the viability of peroxodisulfates or active chlorine. Results obtained in this research clearly demonstrated that the effect of the electrogenerated strong oxidant species, peroxodisulfates or active chlorine, depends on electrocatalytic mechanism followed on BDD surface, improving the color and COD removal.

Four SPs were derived from hemolysin of Escherichia coli, RTX pro

Four SPs were derived from hemolysin of Escherichia coli, RTX protein of V. cholerae, hemolysin of V. anguillarum, zinc-metalloprotease of V. anguillarum, respectively, and their abilities to support secretion of green fluorescent protein (GFP) in an attenuated

V. anguillarum strain MVAV6203 were assayed. Immunodetection of GFP showed that the capability of the tested signal leaders to direct secretion of GFP varied greatly. Although all the four signal peptide-fused GFPs could be expressed correctly and trapped intracellularly in recombinant strains, only the EmpA signal peptide could confer efficient 5-Fluoracil secretion to GFP. For the investigation of its potential application in live bacteria carrier vaccines, a heterologous protein EseB of Edwardsiella tarda was fused to the SP (empA) antigen-delivery system and introduced into the strain MVAV6203. Further analysis of EseB demonstrated that the constructed SP (empA) antigen-delivery PD-1/PD-L1 Inhibitor 3 in vitro system could be used to secrete foreign protein

in attenuated V. anguillarum and be available for carrier vaccines development.”
“(Z)-2-amino-1,5-dihydro-1-methyl-5-[4-(mesyl)benzylidene]-4H-imidazol-4-one mesilate (ZLJ-601) is an imidazolone COX/5-LOX inhibitor, which has excellent anti-inflammatory activity with an improved gastrointestinal safety profile. The purpose of this study was to evaluate the in vivo absorption, distribution, metabolism, and excretion of ZLJ-601 in Sprague-Dawley rats. After intravenous or intragastric administration to rats, the concentration of ZLJ-601 in plasma, bile, urine, feces and various types of tissues was detected by LC-MS. We also conducted the identification of metabolites using tandem mass spectrometry. After the intravenous administration, the t(1/2) ranged ON-01910 from 38.71 to 42.62 min and the AUC increased in a

dose-proportional manner. After oral dosing, the plasma level of ZLJ-601 peaked at 28.33 min, having a C-max value of 0.26 mg/l, and the bioavailability was only 4.92%. The highest tissue concentration of ZLJ-601 was observed in lung and kidney, but it was not found in brain. The majority of unchanged ZLJ-601 was excreted in urine (similar to 35.87%) within 36 h. Two main metabolites are the hydroxylation product and the glucuronide conjugate of the hydroxylation product. Copyright (C) 2012 S. Karger AG, Basel”
“Spatial diversity gradients are a pervasive feature of life on Earth. We examined a global ocean circulation, biogeochemistry, and ecosystem model that indicated a decrease in phytoplankton diversity with increasing latitude, consistent with observations of many marine and terrestrial taxa. In the modeled subpolar oceans, seasonal variability of the environment led to competitive exclusion of phytoplankton with slower growth rates and lower diversity.