We investigate which spaces are obtained when considering the limiting class of real interpolation spaces (0,q;J) for ordered Banach couples of spaces of (scalar) integrable functions with respect to ...a vector measure m, defined on a σ-algebra, with values in a Banach space. If m is in particular a finite positive scalar measure, previous known results are derived from ours. Furthermore, we study the interpolation of p-th power factorable operators by the extreme real interpolation method (1,q;K). We also deduce interpolation results for the (1,q;K)-method that apply to other related classes of operators to p-th power factorable operators, such as bidual (p,q)-power-concave operators and q-concave operators.
The consolidation of spatial memory depends on the reactivation ('replay') of hippocampal place cells that were active during recent behaviour. Such reactivation is observed during sharp-wave ripples ...(SWRs)-synchronous oscillatory electrical events that occur during non-rapid-eye-movement (non-REM) sleep
and whose disruption impairs spatial memory
. Although the hippocampus also encodes a wide range of non-spatial forms of declarative memory, it is not yet known whether SWRs are necessary for such memories. Moreover, although SWRs can arise from either the CA3 or the CA2 region of the hippocampus
, the relative importance of SWRs from these regions for memory consolidation is unknown. Here we examine the role of SWRs during the consolidation of social memory-the ability of an animal to recognize and remember a member of the same species-focusing on CA2 because of its essential role in social memory
. We find that ensembles of CA2 pyramidal neurons that are active during social exploration of previously unknown conspecifics are reactivated during SWRs. Notably, disruption or enhancement of CA2 SWRs suppresses or prolongs social memory, respectively. Thus, SWR-mediated reactivation of hippocampal firing related to recent experience appears to be a general mechanism for binding spatial, temporal and sensory information into high-order memory representations, including social memory.
Orienting covert exogenous (involuntary) attention to a target location improves performance in many visual tasks 1, 2. It is unknown whether early visual cortical areas are necessary for this ...improvement. To establish a causal link between these areas and attentional modulations, we used transcranial magnetic stimulation (TMS) to briefly alter cortical excitability and determine whether early visual areas mediate the effect of exogenous attention on performance. Observers performed an orientation discrimination task. After a peripheral valid, neutral, or invalid cue, two cortically magnified gratings were presented, one in the stimulated region and the other in the symmetric region in the opposite hemifield. Observers received two successive TMS pulses around their occipital pole while the stimuli were presented. Shortly after, a response cue indicated the grating whose orientation observers had to discriminate. The response cue either matched—target stimulated—or did not match—distractor stimulated—the stimulated side. Grating contrast was varied to measure contrast response functions (CRF) for all combinations of attention and TMS conditions. When the distractor was stimulated, exogenous attention yielded response gain—performance benefits in the valid-cue condition and costs in the invalid-cue condition compared with the neutral condition at the high contrast levels. Crucially, when the target was stimulated, this response gain was eliminated. Therefore, TMS extinguished the effect of exogenous attention. These results establish a causal link between early visual areas and the modulatory effect of exogenous attention on performance.
•Investigated how TMS affects the typical benefits and costs of exogenous attention•Identical TMS for all cueing conditions guided by individuals’ phosphene mapping•TMS to occipital cortex extinguished the perceptual effects of exogenous attention•Causal link between V1-V2 and exogenous attention’s effect on visual perception
Fernández and Carrasco show that TMS locked to stimulus onset after deployment of exogenous spatial attention extinguishes its typical benefits and costs on a visual discrimination task. Using a psychophysics-TMS protocol, the authors provide a causal link between early visual areas and exogenous attention’s effect on visual perception.
Gait disorders can reduce the quality of life for people with neuromuscular impairments. Therefore, walking recovery is one of the main priorities for counteracting sedentary lifestyle, reducing ...secondary health conditions and restoring legged mobility. At present, wearable powered lower-limb exoskeletons are emerging as a revolutionary technology for robotic gait rehabilitation. This systematic review provides a comprehensive overview on wearable lower-limb exoskeletons for people with neuromuscular impairments, addressing the following three questions: (1) what is the current technological status of wearable lower-limb exoskeletons for gait rehabilitation?, (2) what is the methodology used in the clinical validations of wearable lower-limb exoskeletons?, and (3) what are the benefits and current evidence on clinical efficacy of wearable lower-limb exoskeletons? We analyzed 87 clinical studies focusing on both device technology (e.g., actuators, sensors, structure) and clinical aspects (e.g., training protocol, outcome measures, patient impairments), and make available the database with all the compiled information. The results of the literature survey reveal that wearable exoskeletons have potential for a number of applications including early rehabilitation, promoting physical exercise, and carrying out daily living activities both at home and the community. Likewise, wearable exoskeletons may improve mobility and independence in non-ambulatory people, and may reduce secondary health conditions related to sedentariness, with all the advantages that this entails. However, the use of this technology is still limited by heavy and bulky devices, which require supervision and the use of walking aids. In addition, evidence supporting their benefits is still limited to short-intervention trials with few participants and diversity among their clinical protocols. Wearable lower-limb exoskeletons for gait rehabilitation are still in their early stages of development and randomized control trials are needed to demonstrate their clinical efficacy.
The Mpemba effect occurs when a hot system cools faster than an initially colder one, when both are refrigerated in the same thermal reservoir. Using the custom-built supercomputer Janus II, we study ...the Mpemba effect in spin glasses and show that it is a nonequilibrium process, governed by the coherence length ξ of the system. The effect occurs when the bath temperature lies in the glassy phase, but it is not necessary for the thermal protocol to cross the critical temperature. In fact, the Mpemba effect follows from a strong relationship between the internal energy and ξ that turns out to be a sure-tell sign of being in the glassy phase. Thus, the Mpemba effect presents itself as an intriguing avenue for the experimental study of the coherence length in supercooled liquids and other glass formers.
Covert spatial attention (without concurrent eye movements) improves performance in many visual tasks (e.g., orientation discrimination and visual search). However, both covert attention ...systems-endogenous (voluntary) and exogenous (involuntary)-exhibit differential effects on performance in tasks mediated by spatial and temporal resolution suggesting an underlying mechanistic difference. We investigated whether these differences manifest in sensory tuning by assessing whether and how endogenous and exogenous attention differentially alter the representation of two basic visual dimensions-orientation and spatial frequency (SF). The same human observers detected a grating embedded in noise in two separate experiments (with endogenous or exogenous attention cues). Reverse correlation was used to infer the underlying neural representation from behavioral responses, and we linked our results to established neural computations via a normalization model of attention. Both endogenous and exogenous attention similarly improved performance at the attended location by enhancing the gain of all orientations without changing tuning width. In the SF dimension, endogenous attention enhanced the gain of SFs above and below the target SF, whereas exogenous attention only enhanced those above. Additionally, exogenous attention shifted peak sensitivity to SFs above the target SF, whereas endogenous attention did not. Both covert attention systems modulated sensory tuning via the same computation (gain changes). However, there were differences in the strength of the gain. Compared with endogenous attention, exogenous attention had a stronger orientation gain enhancement but a weaker overall SF gain enhancement. These differences in sensory tuning may underlie differential effects of endogenous and exogenous attention on performance.
Covert spatial attention is a fundamental aspect of cognition and perception that allows us to selectively process and prioritize incoming visual information at a given location. There are two types: endogenous (voluntary) and exogenous (involuntary). Both typically improve visual perception, but there are instances where endogenous improves perception but exogenous hinders perception. Whether and how such differences extend to sensory representations is unknown. Here we show that both endogenous and exogenous attention mediate perception via the same neural computation-gain changes-but the strength of the orientation gain and the range of enhanced spatial frequencies depends on the type of attention being deployed. These findings reveal that both attention systems differentially reshape the tuning of features coded in striate cortex.
Gabor filtering is a widely adopted technique for texture analysis. The design of a Gabor filter bank is a complex task. In texture classification, in particular, Gabor filters show a strong ...dependence on a certain number of parameters, the values of which may significantly affect the outcome of the classification procedures. Many different approaches to Gabor filter design, based on mathematical and physiological consideration, are documented in literature. However, the effect of each parameter, as well as the effects of their interaction, remain unclear. The overall aim of this work is to investigate the effects of Gabor filter parameters on texture classification. An extensive experimental campaign has been conducted. The outcomes of the experimental activity show a significant dependence of the percentage of correct classification on the smoothing parameter of the Gabor filters. On the contrary, the correlation between the number of frequencies and orientations used to define a filter bank and the percentage of correct classification appeared to be poor.
Genomic studies have yielded important insights into the pathogenesis of obesity. Circulating microRNAs (miRNAs) are valuable biomarkers of systemic diseases and potential therapeutic targets. We ...sought to define the circulating pattern of miRNAs in obesity and examine changes after weight loss.
We assessed the genomewide circulating miRNA profile cross-sectionally in 32 men and after surgery-induced weight loss in 6 morbidly obese patients. The most relevant miRNAs were cross-sectionally validated in 80 men and longitudinally in 22 patients (after surgery-induced weight loss). We evaluated the effects of diet-induced weight loss in 9 obese patients. Thirty-six circulating miRNAs were associated with anthropometric variables in the initial sample.
In the validation study, morbidly obese patients showed a marked increase of miR-140-5p, miR-142-3p (both P < 0.0001), and miR-222 (P = 0.0002) and decreased levels of miR-532-5p, miR-125b, miR-130b, miR-221, miR-15a, miR-423-5p, and miR-520c-3p (P < 0.0001 for all). Interestingly, in silico targets leukemia inhibitory factor receptor (LIFR) and transforming growth factor receptor (TGFR) of miR-140-5p, miR-142-3p, miR-15a, and miR-520c-3p circulated in association with their corresponding miRNAs. Moreover, a discriminant function of 3 miRNAs (miR-15a, miR-520c-3p, and miR-423-5p) was specific for morbid obesity, with an accuracy of 93.5%. Surgery-induced (but not diet-induced) weight loss led to a marked decrease of miR-140-5p, miR-122, miR-193a-5p, and miR-16-1 and upregulation of miR-221 and miR-199a-3p (P < 0.0001 for all).
Circulating miRNAs are deregulated in severe obesity. Weight loss-induced changes in this profile and the study of in silico targets support this observation and suggest a potential mechanistic relevance.
Aim
To assess periodontal stability and the association between tooth‐ and patient‐related factors and tooth loss during supportive periodontal care (SPC).
Materials and Methods
A prospective ...observational study was carried out on previously treated periodontitis patients followed up for 5 years in SPC. The risk profile (low, moderate, high) of each patient based on periodontal risk assessment (PRA) scoring at baseline was evaluated, and tooth loss rates were analysed.
Results
Two hundred patients were included in the study, and 143 had 5‐year follow‐up data available for analysis. The overall annual tooth loss per patient was 0.07 ± 0.14 teeth/patient/year. Older age, smoking, staging and grading were associated with increased tooth loss rates. Most patients whose teeth were extracted belonged to the PRA high‐risk group. Both PRA and a tooth prognosis system used at baseline showed high negative predictive value but low positive predictive value for tooth loss during SPC.
Conclusions
Overall, the tooth loss rate of periodontitis patients in this prospective cohort study under SPC in private practice was low. Both tooth‐based and patient‐based prognostic systems can identify high‐risk cases, but their positive predictive value should be improved.
Nanoplasmonics is the emerging research field that studies light–matter interactions mediated by resonant excitations of surface plasmons in metallic nanostructures. It allows the manipulation of the ...flow of light and its interaction with matter at the nanoscale (10−9 m). One of the most promising characteristics of plasmonic resonances is that they occur at frequencies corresponding to typical electronic excitations in matter. This leads to the appearance of strong interactions between localized surface plasmons and light emitters (such as molecules, dyes, or quantum dots) placed in the vicinity of metals. Recent advances in nanofabrication and the development of novel concepts in theoretical nanophotonics have opened the way to the design of structures aimed to reduce the lifetime and enhance the decay rate and quantum efficiency of available emitters. In this article, some of the most relevant experimental and theoretical achievements accomplished over the last several years are presented and analyzed.
The emission properties of emitters positioned near a nanoantenna can be drastically influenced by the high fields generated. The most relevant concepts that are driving the development of current nanoplasmonics are reviewed, and a simple description is provided for recently developed theoretical approaches and experimental techniques aimed to tailor the optical response of metal nanostructures through plasmonics.
PDF
