Signatures of criticality arise in simple neural population models with correlations

Large-scale recordings of neuronal activity make it possible to gain insights into the collective activity of neural ensembles. It has been hypothesized that neural populations might be optimized to operate at a 'thermodynamic critical point', and that this property has implications for information processing. Support for this notion has come from a series of studies which identified statistical signatures of criticality in the ensemble activity of retinal ganglion cells. What are the underlying mechanisms that give rise to these observations? Here we show that signatures of criticality arise even in simple feed-forward models of retinal population activity. In particular, they occur whenever neural population data exhibits correlations, and is randomly sub-sampled during data analysis. These results show that signatures of criticality are not necessarily indicative of an optimized coding strategy, and challenge the utility of analysis approaches based on equilibrium thermodynamics for understanding partially observed biological systems.Comment: 36 pages, LaTeX; added journal reference on page 1, added link to code repositor

Hoffman’s Error Bounds and Uniform Lipschitz Continuity of Best l(p) -Approximations

In a central paper on smoothness of best approximation in 1968 R. Holmes and B. Kripke proved among others that on ℝn, endowed with the lρ-norm, 1\u3c p \u3c ∞, the metric projection onto a given linear subspace is Lipschitz continuous where the Lipschitz constant depended on the parameter p. Using Hoffman’s Error Bounds as a principal tool we prove uniform Lipschitz continuity of best lρ -ap- proximations. As a consequence, we reprove and prove, respectively, Lipschitz. continuity of the strict best approximation (sba, p = ∞ and of the natural best approximation (nba, p = 1

Nourishment level affects caste-related gene expression in Polistes wasps

Background: Social insects exhibit striking phenotypic plasticity in the form of distinct reproductive (queen) and non-reproductive (worker) castes, which are typically driven by differences in the environment during early development. Nutritional environment and nourishment during development has been shown to be broadly associated with caste determination across social insect taxa such as bees, wasps, and termites. In primitively social insects such as Polistes paper wasps, caste remains flexible throughout adulthood, but there is evidence that nourishment inequalities can bias caste development with workers receiving limited nourishment compared to queens. Dominance and vibrational signaling are behaviors that have also been linked to caste differences in paper wasps, suggesting that a combination of nourishment and social factors may drive caste determination. To better understand the molecular basis of nutritional effects on caste determination, we used RNA-sequencing to investigate the gene expression changes in response to proteinaceous nourishment deprivation in Polistes metricus larvae. Results: We identified 285 nourishment-responsive transcripts, many of which are related to lipid metabolism and oxidation-reduction activity. Via comparisons to previously identified caste-related genes, we found that nourishment restriction only partially biased wasp gene expression patterns toward worker caste-like traits, which supports the notion that nourishment, in conjunction with social environment, is a determinant of developmental caste bias. In addition, we conducted cross-species comparisons of nourishment-responsive genes, and uncovered largely lineage-specific gene expression changes, suggesting few shared nourishment-responsive genes across taxa. Conclusion: Overall, the results from this study highlight the complex and multifactorial nature of environmental effects on the gene expression patterns underlying plastic phenotypes

Das schilddrüsenähnliche follikuläre Nierenzellkarzinom

Das schilddrüsenähnliche follikuläre Nierenzellkarzinom wurde auf der Grundlage von bisher 9 Fallbeschreibungen als eigenständige Nierentumorentität postuliert. Diese neue Tumorentität ist bis dato nicht in der Tumorklassifikation der World Health Organisation (WHO) aufgeführt. Wir beschreiben hier einen weiteren Fall, der als Zufallsbefund bei der Autopsie eines 58-jährigen Patienten identifiziert wurde. Der Patient verstarb an den Folgen einer akuten myeloischen Leukämie nach Chemotherapie und hatte zusätzlich ein Adenokarzinom der Prostata. Der Nierentumor war im Nierenoberpol links lokalisiert und hatte einen Durchmesser von 3 cm bei grau-brauner Schnittfläche. Histologisch zeigte der Tumor das typische schilddrüsenähnliche mikro- und makrofollikuläre Bild sowie eosinophiles intrafollikuläres kolloidähnliches Material mit teils multifokalen Verkalkungsherden. Immunhistologisch war er CD10-positiv sowie TTF1- (thyroidaler Transkriptionsfaktor-1-) und Thyreoglobulin-negativ. Die Zusammenschau der publizierten Fälle zeigt, dass diese Tumoren ein geringes Metastasierungsrisiko besitzen. Die bisherigen Erfahrungen mit diesem Tumor sind allerdings zu gering, um das schilddrüsenähnliche follikuläre Nierenzellkarzinom als eigenständige Tumorentität für die nächste WHO-Klassifikation uneingeschränkt empfehlen zu können. = Thyroid-like follicular carcinoma of the kidney is postulated as a potentially new entity of renal tumor based on nine previously published case reports. This tumor entity is not yet integrated into the classification of tumors of the World Health Organization (WHO). In this article a new case of thyroid-like follicular carcinoma of kidney is described which was incidentally detected at autopsy. The 58-year-old patient died of complications of acute myeloid leukemia after chemotherapy and also had prostatic adenocarcinoma. The renal tumor in the left kidney had a diameter of 3 cm and showed a grey-brown cut surface. Histologically, the tumor presented with a typical thyroid-like microfollicular and macrofollicular structure filled with eosinophilic, colloid-like material with calcification. Immunohistologically the renal tumor was CD 10 positive and negative for thyroid transcription factor 1 (TTF1) and thyroglobulin. A synopsis of the published case reports indicates that thyroid-like follicular carcinoma of the kidney has a low risk of metastasis. More experience with further cases of thyroid-like follicular renal carcinoma is necessary before a recommendation of a separate tumor entity in the next WHO classification is justified

Das schilddrüsenähnliche follikuläre Nierenzellkarzinom: Eine eigene Tumorentität?

Zusammenfassung: Das schilddrüsenähnliche follikuläre Nierenzellkarzinom wurde auf der Grundlage von bisher 9 Fallbeschreibungen als eigenständige Nierentumorentität postuliert. Diese neue Tumorentität ist bis dato nicht in der Tumorklassifikation der World Health Organisation (WHO) aufgeführt. Wir beschreiben hier einen weiteren Fall, der als Zufallsbefund bei der Autopsie eines 58-jährigen Patienten identifiziert wurde. Der Patient verstarb an den Folgen einer akuten myeloischen Leukämie nach Chemotherapie und hatte zusätzlich ein Adenokarzinom der Prostata. Der Nierentumor war im Nierenoberpol links lokalisiert und hatte einen Durchmesser von 3cm bei grau-brauner Schnittfläche. Histologisch zeigte der Tumor das typische schilddrüsenähnliche mikro- und makrofollikuläre Bild sowie eosinophiles intrafollikuläres kolloidähnliches Material mit teils multifokalen Verkalkungsherden. Immunhistologisch war er CD10-positiv sowie TTF1- (thyroidaler Transkriptionsfaktor-1-) und Thyreoglobulin-negativ. Die Zusammenschau der publizierten Fälle zeigt, dass diese Tumoren ein geringes Metastasierungsrisiko besitzen. Die bisherigen Erfahrungen mit diesem Tumor sind allerdings zu gering, um das schilddrüsenähnliche follikuläre Nierenzellkarzinom als eigenständige Tumorentität für die nächste WHO-Klassifikation uneingeschränkt empfehlen zu können

Evidence for Contemporary Switching of the O-Antigen Gene Cluster between Shiga Toxin-Producing Escherichia coli Strains Colonizing Cattle

Shiga toxin-producing Escherichia coli (STEC) comprise a group of zoonotic enteric pathogens with ruminants, especially cattle, as the main reservoir. O-antigens are instrumental for host colonization and bacterial niche adaptation. They are highly immunogenic and, therefore, targeted by the adaptive immune system. The O-antigen is one of the most diverse bacterial cell constituents and variation not only exists between different bacterial species, but also between individual isolates/strains within a single species. We recently identified STEC persistently infecting cattle and belonging to the different serotypes O156:H25 (n = 21) and O182:H25 (n = 15) that were of the MLST sequence types ST300 or ST688. These STs differ by a single nucleotide in purA only. Fitness-, virulence-associated genome regions, and CRISPR/CAS (clustered regularly interspaced short palindromic repeats/CRISPR associated sequence) arrays of these STEC O156:H25 and O182:H25 isolates were highly similar, and identical genomic integration sites for the stx converting bacteriophages and the core LEE, identical Shiga toxin converting bacteriophage genes for stx1a, identical complete LEE loci, and identical sets of chemotaxis and flagellar genes were identified. In contrast to this genomic similarity, the nucleotide sequences of the O-antigen gene cluster (O-AGC) regions between galF and gnd and very few flanking genes differed fundamentally and were specific for the respective serotype. Sporadic aEPEC O156:H8 isolates (n = 5) were isolated in temporal and spatial proximity. While the O-AGC and the corresponding 5′ and 3′ flanking regions of these aEPEC isolates were identical to the respective region in the STEC O156:H25 isolates, the core genome, the virulence associated genome regions and the CRISPR/CAS elements differed profoundly. Our cumulative epidemiological and molecular data suggests a recent switch of the O-AGC between isolates with O156:H8 strains having served as DNA donors. Such O-antigen switches can affect the evaluation of a strain's pathogenic and virulence potential, suggesting that NGS methods might lead to a more reliable risk assessment

Open-label trial with artemether-lumefantrine against uncomplicated Plasmodium falciparum malaria three years after its broad introduction in Jimma Zone, Ethiopia

Background: In Jimma Zone, Ethiopia, the first-line treatment of uncomplicated falciparum malaria has been changed from sulphadoxine-pyrimethamine (SP) to artemether-lumefantrine (AL) in 2006. The objective of this study was to assess the effectiveness of AL in Jimma Zone two to three years after its broad introduction. Methods: An open-label, single-arm, 42-day study of AL against falciparum malaria was conducted in four areas with moderate transmission in Jimma Zone between November 2008 and January 2009 and between August and December 2009. Patients (one-81 years) with uncomplicated Plasmodium falciparum mono-infection were consecutively enrolled. Follow-up visits were at day 2, 3, 7, 28 and 42 or any other day if symptoms reoccurred. Primary and secondary endpoints were PCR-corrected and uncorrected cure rates (molecular differentiation between recrudescence and re-infection) on days 28 and 42. Other secondary endpoints were gametocytaemia at day 7 and day 28, parasitaemia at day 2 and 3, and re-infection rates at day 28 and day 42. Results: Of 348 enrolled patients, 313 and 301 completed follow-up at day 28 and at day 42, respectively. No early treatment failure occurred. For per protocol analysis, PCR-uncorrected cure rates at day 28 and 42 were 99.1% (95% CI 98.0-100.0) and 91.1% (95% CI 87.9-94.3), respectively. PCR-corrected cure rates at day 28 and 42 were 99.4% (95% CI 98.5-100.0) and 94.7% (95% CI 92.2-97.2), respectively. PCR-corrected cure rate at day 42 for children <= 5 years was 90.6% (95% CI 82.4-98.7) only. Adverse events were in general mild to moderate. Incidence of new infections was 3.4% during 42 days, no new infections with Plasmodium vivax were observed. Microscopically detected gametocytaemia was reduced by 80% between day 0 and day 7. Conclusion: In general, AL was effective and well tolerated in Jimma Zone, Ethiopia. However, the PCR-corrected recrudescence rate per-protocol at day 42 for children <= 5 years was 9.4%. Therefore, further development should be monitored on a regular basis as recommended by WHO

The Glass Transition Temperature of Water: A Simulation Study

We report a computer simulation study of the glass transition for water. To mimic the difference between standard and hyperquenched glass, we generate glassy configurations with different cooling rates and calculate the $T$ dependence of the specific heat on heating. The absence of crystallization phenomena allows us, for properly annealed samples, to detect in the specific heat the simultaneous presence of a weak pre-peak (``shadow transition''), and an intense glass transition peak at higher temperature. We discuss the implications for the currently debated value of the glass transition temperature of water. We also compare our simulation results with the Tool-Narayanaswamy-Moynihan phenomenological model.Comment: submitted to Phys. Re