157 research outputs found
Role of the odorant receptor in neuronal connectivity in the olfactory bulb
No full textOlfaction is a highly sophisticated sensory modality able to detect and discriminate thousands of different odours, even at very low concentration. How such a challenging task is achieved remains to be fully understood. A unique feature of the olfactory system is the dual role of the odorant receptor: it does detect odours in the olfactory epithelium but it also contributes to neuronal circuit formation in the olfactory bulb. The odorant receptors are indeed expressed on the cilia that protrude in the nasal cavity, where they bind odorants, and at the axon termini, where they could act as axon guidance molecules. In this review we discuss findings that show how the odorant receptor contributes in regulating neuronal connectivity
Quasi-Universal Length Scale of River Anabranches
No full textLooping patterns, where channels divide and reconnect further downstream, are widespread in natural rivers. Here, we build an extensive dataset of different gravel-bed and sand-bed rivers around the world encompassing a wide range of physiographic and sedimentological conditions. Field data show the existence of quasi-universal relations for the anabranches length when scaled with bankfull hydraulic geometry variables of the main upstream channel. The dimensionless length is found to be nearly slope-invariant, identifying a clear difference with respect to deltaic systems. This scaling relationship is explained by interpreting the dynamics of river loops as basically controlled by a two-way interaction between their constitutive elements, bifurcations and confluences. The identification of a quasi-universal length scale provides insight on the morphological evolution of multi-thread networks and constitutes a key information for the design of self-sustaining river restoration interventions
Modeling Steady Grain Sorting in River Bifurcations
No full textA striking feature of rivers is their ability to sort the sediments composing them. One of the chief causes for grain sorting consists in the selective transport of different sizes moving downstream. This process can be substantially influenced by the presence of lateral topographic variations, as those produced by channel bifurcations, in which water and sediment are diverted between two smaller anabranches. In particular, field and laboratory observations have shown that the asymmetric flux distribution commonly observed in actual bifurcations is associated with a coarsening of the most-carrying branch. Here, equilibrium sorting in river bifurcations is addressed through a quasi-2D model. Differently from previous works, a fully physically based description of the processes tied to a heterogeneous sediment mixture is introduced. The main mechanisms consist in the lateral pull of sediment due to a sloping bed upstream the bifurcation, and the variation of transport capacity in downstream branches. The model indicates that grain sorting tends to reduce the degree of flux asymmetry between branches for increasing heterogeneity of the mixture. Moreover, the uneven discharge distribution is associated with a different bed surface composition, with bed coarsening of the dominating channel and fining of the other branch. The reduced sediment transport asymmetry and bed surface fining enhance the transport of fine material in the less-carrying branch, thus contributing to keep it morphologically active. Finally, the model predicts an overall fining of bed surface material with respect to the feeder channel
Processing adjectives in development: Evidence from eye-tracking
No full textCombining adjective meaning with the modified noun is particularly challenging for children under three years. Previous research suggests that in processing noun-adjective phrases children may over-rely on noun information, delaying or omitting adjective interpretation. However, the question of whether this difficulty is modulated by semantic differences among (subsective) adjectives is underinvestigated.A visual-world experiment explores how Italian-learning children (N=38, 2;4-5;3) process noun-adjective phrases and whether their processing strategies adapt based on the adjective class. Our investigation substantiates the proficient integration of noun and adjective semantics by children. Nevertheless, alligning with previous research, a notable asymmetry is evident in the interpretation of nouns and adjectives, the latter being integrated more slowly. Remarkably, by testing toddlers across a wide age range, we observe a developmental trajectory in processing, supporting a continuity approach to children's development. Moreover, we reveal that children exhibit sensitivity to the distinct interpretations associated with each subsective adjective
Cascina colombarazza – Comune di Cremona (sito 54)
No full textNel corso dello splateamento per la posa del metanodotto SNAM è stato intercettato un sito, denominato sito 54, a N della via Postumia, presso la casina Colombarazza in comune di Cremona. Vi si possono individuare tre distinte fasi cronologiche di occupazione: quella denominata fase I fa riferimento ad una serie di sottostrutture databili al BM (BMI-BMIII), interpretabili come area perimetrale di un insediamento, il cui nucleo centrale non è stato intercettato
Intracellular calcium dysregulation by the alzheimer’s disease-linked protein presenilin 2
No full textAlzheimer’s disease (AD) is the most common form of dementia. Even though most AD cases are sporadic, a small percentage is familial due to autosomal dominant mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes. AD mutations contribute to the generation of toxic amyloid β (Aβ) peptides and the formation of cerebral plaques, leading to the formulation of the amyloid cascade hypothesis for AD pathogenesis. Many drugs have been developed to inhibit this pathway but all these approaches currently failed, raising the need to find additional pathogenic mechanisms. Alterations in cellular calcium (Ca2+) signaling have also been reported as causative of neurodegeneration. Interestingly, Aβ peptides, mutated presenilin-1 (PS1), and presenilin-2 (PS2) variously lead to modifications in Ca2+ homeostasis. In this contribution, we focus on PS2, summarizing how AD-linked PS2 mutants alter multiple Ca2+ pathways and the functional consequences of this Ca2+ dysregulation in AD pathogenesis
Nocturnal Cardiac Arrhythmias in Heart Failure With Obstructive and Central Sleep Apnea
No full textBackground: Both obstructive and central sleep apnea (CSA) may contribute to nocturnal cardiac arrhythmias (NCAs). Data are scarce regarding the prevalence of clinically important nocturnal atrial and ventricular arrythmias in patients with heart failure with reduced ejection fraction (HFrEF) and OSA or CSA. Research Question: In a cohort of patients with HFrEF, how does the prevalence of NCA compare among those with OSA, CSA, and those with no to mild sleep apnea? Is the severity of OSA or CSA associated with atrial and ventricular NCAs? Study Design and Methods: This cross-sectional analysis is an ancillary study of the Effect of Adaptive Servo Ventilation on Survival and Hospital Admissions in Heart Failure (ADVENT-HF) trial. We compared the prevalence of NCAs (excessive supraventricular ectopic activity [ESVEA], defined as premature atrial complexes ≥ 30/h or supraventricular tachycardia ≥ 20 beats); atrial fibrillation/flutter [AF]; and > 10 premature ventricular complexes [PVCs/h]) on ECGs from polysomnograms of patients with HFrEF between those with OSA (apnea-hypopnea index [AHI ≥ 15 events/h]), those with CSA (AHI ≥ 15 events/h), and those with no to mild sleep apnea (AHI < 15 events/h [control]). Results: The prevalence of ESVEA was higher in patients with OSA (n = 430) and CSA (n = 150) compared with control participants (n = 76): 0%, 9%, and 12%, respectively. The prevalence of AF in the control, OSA, and CSA groups was 9%, 17%, and 27%; the prevalence of > 10 PVCs/h was 45%, 59%, and 63%. In multivariable regression analyses, premature atrial complexes/h was associated with OSA severity (obstructive AHI: 22.4% increase per 10 events/h [95% CI, 5.2-42.3; P = .009), although neither obstructive nor central AHI was associated with AF or > 10 PVC/h. Interpretation: In patients with HFrEF, the prevalences of nocturnal ESVEA, AF, and PVC > 10/h were higher in those with OSA or CSA than in those without OSA or CSA, and OSA severity was related to the burden of nocturnal atrial ectopy. Severity of OSA or CSA was not significantly related to AF or > 10 PVC/h. Clinical Trial Registration: ClinicalTrials.gov; No.: NCT01128816; URL: www.clinicaltrials.go
THE ROLE OF SPONTANEOUS ACTIVITY IN SCULPITNG CIRCUIT FORMATION AND FUNCTION IN THE OLFACTORY BULB
No full textLaboratory data - physical modelling of gravel bed rivers under unsteady flow conditions
No full textSediment transport and topography data from laboratory experiments under unsteady flow conditions.
Data supporting the manuscript:
Redolfi, M., Bertoldi, W., Tubino, M., & Welber, M. (2018). Bed load variability and morphology of gravel bed rivers
subject to unsteady flow: A laboratory investigation. Water Resources Research, 54, 842–862. https://doi.org/
10.1002/2017WR021143
Details about the physical model and the experimental procedure can be found in the paper.For further information please contact the corresponding author at [email protected]
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