it is difficult to consider all these choices in one single model, although an integrated model is the final goal. Also, even with today's computing power, an integrated model will inevitably require some strict assumptions that will reduce its application value to local specific problems. The classical way to forecast the results of such a complex choice process is to divide it into simpler subprocesses in a logical and tractable way. Models for these subprocesses are then developed individually, and the hope is that they can eventually be assembled to provide useful predictions for decision makers. The past half-century has witnessed several different methods of disentangling the complex travel decision-making process. Two major approaches have emerged over time: trip-and activity-based approaches. The traditional four-step travel forecasting models are often referred to as trip-based approaches in that they treat individual trips as the elementary subjects. In so doing, the four-step model tends to ignore the diversity among different individuals and considers aggregate travel choices in four steps-trip generation, trip distribution, mode split, and route assignment. Other choices are either treated as exogenous (e.g., land use and automobile ownership) or extremely simplified (e.g., trip scheduling). An up-to-date summary of the achievements in this field can be found in the book by Ortuzar and Willumsen (7). There is some disagreement about how to assemble these four subprocesses in travel forecasting. Some researchers are of the opinion that the four steps should be solved in a coherent network equilibrium instead of sequentially. Boyce (8) provides a thorough review of the origin and the recent development of that issue. An important nature of travel demand ignored by trip-based approaches is that travel is a derived demand-travel is desired to participate in other activities, not for its own consumption value. In view of this and other inadequacies of the four-step model, activity analysis has been applied to travel demand analysis since the 1970s. Activitybased approaches describe which activities people pursue, where, when, and for how long given fixed land use, transportation supply, and individual characteristics. A trip is generated to connect two spatially separated sequential activities. In activity-based approaches, every individual is a decision maker who confronts a huge choice set of various activity patterns in the time-space domain. Each combination of activities and their locations, starting points, and durations forms a unique activity pattern. Individuals select (or at least intend to select) the patterns that maximize their utilities by somehow solving a large-scale combinatorial optimization problem conditional on others' decisions. Different from the trip-based models, activity-based approaches deem individuals' decision making as subprocesses of the emergence of travel demand. These subprocesses are typically assembled by microscopic travel simulation to form aggregate travel forecasti...

Due to the number of confirmed cases and casualties of the new COVID-19 virus diminishing day after day, several countries around the world are discussing on how to return to the new normal way of life. In order to keep the spread of the disease under control and avoid a second wave of infection, one alternative being considered is the utilization of contact tracing. However, despite several alternatives being available, contact tracing still faces issues in terms of maintaining user privacy and security, making its mass-adoption quite difficult. Based on that, a novel framework for contact tracing using blockchain as its infrastructure is presented. By integrating blockchain with contact tracing applications, user privacy can be guaranteed, while also providing people and government bodies with a complete public view of all confirmed cases. Moreover, we also investigate how public locations can aid in the contact tracing process by measuring the risk of exposure to COVID-19 to the general public and advertising it in a blockchain. By doing so, these locations can effectively notify of potential infection risks, while also guaranteeing privacy and trustworthiness in the information. Lastly, numerical results are shown in different scenarios and conclusions are drawn.

In the nerve roots of vertebrates, the peripheral nervous system (PNS) and central nervous system (CNS) interface at the PNS-CNS transitional zone (PCTZ), which consists of cell boundaries with various myelin components. We have recently shown that the mouse cochlear nerve presents an exceptionally long segment of the CNS tissue extending into the PNS using light microscopy. However, it is unclear how oligodendrocytes and Schwann cells contribute to the formation of myelin components of the PCTZ. It is undetermined how myelination is initiated along the cochlear nerve, and when it adopts a mature pattern. In this study, immunofluorescence using antibodies specific to oligodendrocyte marker myelin oligodendrocyte glycoprotein (MOG) and Schwann cell marker myelin protein zero (MPZ) were used to detail the expression of myelin components along the postnatal mouse cochlear nerve. We found that the expression of MPZ was initially observed in the soma of bipolar spiral ganglion neurons at postnatal day 0 (P0) and progressed to the central and peripheral processes after P8–P10. Myelination of the CNS tissue was initiated in close proximity to the PCTZ from P7 to P8 and then extended centrally. Myelination of the PCTZ reached a mature style at P14, when the interface of the expression of MOG and MPZ was clearly identified along the cochlear nerve. This knowledge of PCTZ formation of the cochlear nerve will be essential to future myelination research, and it will also gain clinical interest because of its relevance to the degeneration and regeneration of the auditory pathway in hearing impairment.

BackgroundSensory input is generally thought to be necessary for refining and consolidating neuronal connections during brain development. We here report that cortical callosal axons in somatosensory cortex require sensory input for their target selection in contralateral cortex.ResultsEliminating sensory input to either hemisphere by unilateral transection of infraorbital nerve (ION) prevents target selection of callosal axons in contralateral cortex. Strikingly, blocking sensory input bilaterally, by simultaneously transecting both IONs, results in rescued callosal projection. In contrast, non-simultaneous bilateral ION transection has the same effect as unilateral transection. Similar results are obtained by lesion of whisker hair follicles. c-Fos-positive neurons in brain slices treated with KCl is decreased more in contralateral cortex with unilateral removal of sensory input, but decreased similarly in both cortices in mice with simultaneous bilateral removal of sensory input. Frequency of sEPSC of cortical neurons is also reduced in contralateral cortex with the unilateral removal of sensory input, but equally reduced on both sides with the bilateral removal of sensory input, suggesting that unbalanced bilateral sensory input might lead to mismatched neuronal activity between the two cortices and contribute to the formation of callosal projection.ConclusionOur data demonstrate a critical role of balanced bilateral somatosensory input in the formation of callosal connections, and thus reveal a new role of sensory input in wiring brain circuits.

A supinator motor branch to posterior interosseous nerve transfer leads to reliable recovery of thumb and finger extension. Therefore, it is a viable option for C7-T1 brachial plexus palsies.

During locomotion, individuals can determine their positions with either idiothetic cues from movement (path integration systems) or visual landmarks (piloting systems). This project investigated how these 2 systems interact in determining humans' positions. In 2 experiments, participants studied the locations of 5 target objects and 1 single landmark. They walked a path after the targets and the landmark had been removed and then replaced the targets at the end of the path. Participants' position estimations were calculated based on the replaced targets' locations (Mou & Zhang, 2014). In Experiment 1, participants walked a 2-leg path. The landmark reappeared in a different location during or after walking the second leg. The results showed that participants' position estimations followed idiothetic cues in the former case, but the displaced landmark in the latter case. In Experiment 2, participants saw the displaced landmark when they reached the end of the second leg and then walked a third leg without the view of the landmark. Participants were asked or not to point to 1 of the targets before they walked the third leg. The results showed that the initial position of the third leg was still influenced by the displaced landmark in the former case, but was determined by idiothetic cues in the latter case. These results suggest that the path integration system works dynamically and the piloting system resets the path integration system when people judge their positions in the presence of conflicting piloting cues. (PsycINFO Database Record

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The Drosophila larval central nervous system comprises the central brain, ventral nerve cord and optic lobe. In these regions, neuroblasts (NBs) divide asymmetrically to self-renew and generate differentiated neurons or glia. To date, mechanisms of preventing neuron dedifferentiation are still unclear, especially in the optic lobe. Here, we show that the zinc-finger transcription factor Nerfin-1 is expressed in early-stage medulla neurons and is essential for maintaining their differentiation. Loss of Nerfin-1 activates Notch signaling, which promotes neuron-to-NB reversion. Repressing Notch signaling largely rescues dedifferentiation in nerfin-1 mutant clones. Thus, we conclude that Nerfin-1 represses Notch activity in medulla neurons and prevents them from dedifferentiation.