1,158 research outputs found
Nucleus Isthmi Is Required to Sustain Target Pursuit during Visually Guided Prey-Catching
Animals must frequently perform a sequence of behaviors to achieve a specific goal. However, the neural mechanisms that promote the continuation and completion of such action sequences are not well understood. Here, we characterize the anatomy, physiology, and function of the nucleus isthmi (NI), a cholinergic nucleus thought to modulate tectal-dependent, goal-directed behaviors. We find that the larval zebrafish NI establishes reciprocal connectivity with the optic tectum and identify two distinct types of isthmic projection neuron that either connect ipsilaterally to retinorecipient laminae of the tectum and pretectum or bilaterally to both tectal hemispheres. Laser ablation of NI caused highly specific deficits in tectally mediated loom-avoidance and prey-catching behavior. In the context of hunting, NI ablation did not affect prey detection or hunting initiation but resulted in larvae failing to sustain prey-tracking sequences and aborting their hunting routines. Moreover, calcium imaging revealed elevated neural activity in NI following onset of hunting behavior. We propose a model in which NI provides state-dependent feedback facilitation to the optic tectum and pretectum to potentiate neural activity and increase the probability of consecutive prey-tracking maneuvers during hunting sequences
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Large-area ultrathin Te films with substrate-tunable orientation.
Anisotropy in a crystal structure can lead to large orientation-dependent variations of mechanical, optical, and electronic properties. Material orientation control can thus provide a handle to manipulate properties. Here, a novel sputtering approach for 2D materials enables growth of ultrathin (2.5-10 nm) tellurium films with rational control of the crystalline orientation templated by the substrate. The anisotropic Te 〈0001〉 helical chains align in the plane of the substrate on highly oriented pyrolytic graphite (HOPG) and orthogonally to MgO(100) substrates, as shown by polarized Raman spectroscopy and high-resolution electron microscopy. Furthermore, the films are shown to grow in a textured fashion on HOPG, in contrast with previous reports. These ultrathin Te films cover exceptionally large areas (>1 cm2) and are grown at low temperature (25 °C) affording the ability to accommodate a variety of substrates including flexible electronics. They are robust toward oxidation over a period of days and exhibit the non-centrosymmetric P3121 Te structure. Raman signals are acutely dependent on film thickness, suggesting that optical anisotropy persists and is even enhanced at the ultrathin limit. Hall effect measurements indicate orientation-dependent carrier mobility up to 19 cm2 V-1 s-1. These large-area, ultrathin Te films grown by a truly scalable, physical vapor deposition technique with rational control of orientation/thickness open avenues for controlled orientation-dependent properties in semiconducting thin films for applications in electronic and optoelectronic devices.This research was supported by the Air Force Office of Scientific Research grant no. AFOSR-YIP FA9550-17-1-0202 and a 3M Non-Tenured Faculty Award. Elisabeth Bianco acknowledges the support of the National Science Foundation Graduate Research Fellowship under grant no. DGE-1450681. MS acknowledges support from Air Force Office of Scientific Research grant number FA9550-19RYCOR050.
This research made use of instruments in the Shared Equipment Authority of Rice University. This research was supported by the Nanoelectronics Branch, Functional Materials Division, Materials and Manufacturing Directorate, Air Force Research Laboratory and made use of instruments in the Materials Characterization Facility in the Materials and Manufacturing Directorate, Air Force Research Laboratory. We thank Dr Dean Brown for performing the FEM modelling and his contributions to Figure S1. EB thanks Dr Krishnamurthy Mahalingam and Dr Brandon Howe for helpful discussions on TEM and growth
Appropriateness of admission and days of stay in pediatric hospital in Ancona, Italy
Background: In Italy, hospital admission costs account for nearly 42% of total health expenditure; in the Marche region, this share exceeds 50%. High costs of hospitalization, however, can be partly explained by inappropriate use. The aim of this research was to assess the risk factors associated with inappropriate hospital admissions and stay for acute pediatric patients. Methods: Clinical records of children from 30 days to 14 years of age admitted to the wards of orthopedics, pediatrics, pediatric isolation, pediatric surgery and pediatric oncohematology at Salesi Pediatric Hospital of Ancona throughout 2004 were reviewed. The Italian Pediatric Appropriateness Evaluation Protocol (PRUO) was used as a tool for assessing inappropriateness of admission and days of stay. Results: Overall 21.7% (95% CI = 16.1%–22.4%) of hospital admissions and 30.3% (95% CI = 26.0%–34.9%) of days of stay were judged to be inappropriate. Multiple logistic regression analysis indicated that inappropriate admission was significantly associated with type of admission, discharge ward and place of residence. Inappropriateness of stay was significantly higher if admission was to a medical ward and if admission itself was judged inappropriate. Conclusions: In a socioeconomic context in which reducing waste is necessary, ineffective health care interventions are no longer tolerable. As a tool capable of integrating each patient’s specific features with those of the health care process, the pediatric PRUO could be a valid tool in the hands of managers for monitoring the appropriateness of admission and stay
Search for CP violation in D0 and D+ decays
A high statistics sample of photoproduced charm particles from the FOCUS
(E831) experiment at Fermilab has been used to search for CP violation in the
Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We
have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/-
0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) =
+0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second
error is systematic. These asymmetries are consistent with zero with smaller
errors than previous measurements.Comment: 12 pages, 4 figure
A Study of D0 --> K0(S) K0(S) X Decay Channels
Using data from the FOCUS experiment (FNAL-E831), we report on the decay of
mesons into final states containing more than one . We present
evidence for two Cabibbo favored decay modes, and
, and measure their combined branching fraction
relative to to be = 0.0106
0.0019 0.0010. Further, we report new measurements of
=
0.0179 0.0027 0.0026, = 0.0144 0.0032 0.0016,
and = 0.0208 0.0035 0.0021 where the first error is
statistical and the second is systematic.Comment: 11 pages, 3 figures, typos correcte
Integrating transposable elements in the 3D genome
Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome
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The reactive species interactome: evolutionary emergence, biological significance, and opportunities for redox metabolomics and personalized medicine
SIGNIFICANCE: Oxidative stress is thought to account for aberrant redox homeostasis and contribute to aging and disease. However, more often than not administration of antioxidants is ineffective, suggesting our current understanding of the underlying regulatory processes is incomplete. Recent Advances. Similar to reactive oxygen and nitrogen species (ROS, RNS), reactive sulfur species (RSS) are now emerging as important signaling molecules, targeting regulatory cysteine redox switches in proteins, affecting gene regulation, ion transport, intermediary metabolism and mitochondrial function. To rationalize the complexity of chemical interactions of reactive species with themselves and their targets and help define their role in systemic metabolic control, we here introduce a novel integrative concept coined the reactive species interactome (RSI). The RSI is a primeval multi-level redox-regulatory system whose architecture, together with the physicochemical characteristics of its constituents, allows efficient sensing and rapid adaptation to environmental changes and various other stresses to enhance fitness and resilience at the local and whole-organism level.
CRITICAL ISSUES: To better characterise the RSI-related processes that determine fluxes through specific pathways and enable integration, it is necessary to disentangle the chemical biology and activity of reactive species (including precursors and reaction products), their targets, communication systems and effects on cellular, organ and whole-organism bioenergetics using systems-level/network analyses.
FUTURE DIRECTIONS: Understanding the mechanisms through which the RSI operates will enable a better appreciation of the possibilities to modulate the entire biological system; moreover, unveiling molecular signatures that characterize specific environmental challenges or other stresses will provide new prevention/intervention opportunities for personalized medicine
American Thyroid Association Guide to Investigating Thyroid Hormone Economy and Action in Rodent and Cell Models
Background: An in-depth understanding of the fundamental principles that regulate thyroid hormone homeostasis is critical for the development of new diagnostic and treatment ap-proaches for patients with thyroid disease. Summary: Important clinical practices in use today for the treatment of patients with hypothy-roidism, hyperthyroidism, or thyroid cancer, are the result of laboratory discoveries made by scientists investigating the most basic aspects of thyroid structure and molecular biology. In this document, a panel of experts commissioned by the American Thyroid Association makes a se-ries of recommendations related to the study of thyroid hormone economy and action. These recommendations are intended to promote standardization of study design, which should in turn increase the comparability and reproducibility of experimental findings. Conclusions: It is expected that adherence to these recommendations by investigators in the field will facilitate progress towards a better understanding of the thyroid gland and thyroid hormone dependent processes
A Modified Protocol for Bisulfite Genomic Sequencing of Difficult Samples
The bisulfite genomic sequencing protocol is a widely used method for analyzing DNA methylation. It relies on the deamination of unmethylated cytosine residues to uracil; however, its high rates of DNA degradation and incomplete cytosine to uracil conversion often lead to failed experiments, uninformative results, and false positives. Here, we report the addition of a single-step multiple restriction enzyme digestion (MRED) designed to differentially digest polymerase chain reaction products amplified from unconverted DNA while leaving those of converted DNA intact. We show that for our model system, RARB2 P2 promoter, use of MRED increased informative sequencings ninefold, and MRED did not alter the clonal representation in one fully methylated cell line, H-596, treated or not with 5-azadeoxycytidine, a methylation inhibitor. We believe that this method may easily be adapted for analyzing other genes and provide guidelines for selecting the most appropriate MRED restriction enzymes
Food, flavouring and feed plant traditions in the Tyrrhenian sector of Basilicata, Italy
BACKGROUND: Research was carried out in the years 2002–2003 into food, flavouring and feed folk traditions of plants in the Tyrrhenian part of the Basilicata region (southern Italy). This area was colonized in ancient times by Greeks. Data was collected through field interviews, especially of farmers. METHODS: Field data were collected through structured interviews. The informants, numbered 49, belonged to families which had strong links with the traditional activities of the area. RESULTS: 61 taxa are cited, belonging to 26 botanical families, amongst which 44 used as food or flavouring and 22 for animal alimentation. Besides 7 taxa are involved in rituals especially connected with agriculture and plant growth. CONCLUSION: The preservation of some rituals especially concerning agricultural plants is noteworthy in the area, together with a certain degree of continuity in food uses. Knowledge and rediscovery of recipes in human and animal diet could represent an economic potential for the area
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