Erosion versus construction: The origin of Venusian channels

Lava channels are a common feature in the volcanic regions of the Moon, and have now been observed on Venus. There has been much debate about the origin of lunar channels as to whether they are the result of erosional (either thermal or mechanical) or constructional processes. It is necessary to determine the criteria to distinguish between the different types of channels. The clearest evidence is that the presence of levees indicates that the channel experienced a constructional phase for a period. One example of a channel of this type in the southeast region of Aphrodite Terra appears to show both erosional and constructional characteristics. It is approximately 700 km long with an average width of about 1 km. It drops a distance of 700 m from beginning to end, which means that the average slope is 0.06 degrees. Its source may have been a graben situated at the northwest end of the channel. It appears to have different origins along its length. The lack of levees near the source suggests that the channel is erosional in this region. The presence of levees indicates that a constructional phase has occurred. These are formed by lava repeatedly splashing over the channel sides and solidifying. Evidence of levees is seen further away from the source. However, the presence of levees does not mean that the lava was not also eroding and deepening the channel. Thus, in conclusion, our example channel is very sinuous and there is evidence of erosion. There may also have been overflow here. In its middle reaches it roofs over and has the characteristics of a lava tube. In the lower reaches there is strong evidence for the presence of levees indicating construction. On Earth, limited amounts of erosion may occur in basaltic lava channels, although not nearly on the same scale as on the planets just mentioned. For lava erosion on Earth to occur to a comparable extent, excessive eruption times are required. However, low-viscosity komatiite lava may erode to a larger extent and there is direct evidence that carbonatite lava erodes when the underlying strata is also carbonatite. Previously, it has always been assumed that for thermal erosion to occur the flow must be turbulent. Recent findings indicate that this may be a false assumption and that laminar flow may be effective in eroding the substrate

Joseph McNeil Citation for Honorary Degree of Doctor of Humanities

Photocopy of citation for Honorary Doctor of Humanities Degree for Joseph Alfred McNeil by Charles D. Bussey, Chairman of the Board of Trusteeshttps://digital.library.ncat.edu/atfour/1022/thumbnail.jp

An Analysis Of The Title Role In Scapino!

The purpose of this thesis is to serve as documentation of the performance of the title role in Scapino!. It is separated into three parts including a play analysis, a character analysis, and a summation of the rehearsal process. Each section is linked directly to the plays commedia roots, and draws a link between Moliere’s original play Les Fourberies de Scapin, and the work that resulted from the Young Vic’s production Scapino!. The conclusions that are reached serve as an informational tool for the performance of the character of Scapino

Jibreel Khazan (Ezell Blair, Jr.) Citation for Honary Degree of Doctor of Humanities

Photocopy of citation for Honorary Doctor of Humanities Degree for Joseph Alfred McNeil by Charles D. Bussey, Chairman of the Board of Trusteeshttps://digital.library.ncat.edu/atfour/1019/thumbnail.jp

Franklin McCain Citation for Honorary Degree of Doctor of Humanities

Photocopy of citation for Honorary Doctor of Humanities Degree for Franklin McCain by Charles D. Bussey, Chairman of the Board of Trusteeshttps://digital.library.ncat.edu/atfour/1016/thumbnail.jp

Glutamate receptors in perirhinal cortex mediate encoding, retrieval, and consolidation of object recognition memory.

Object recognition is consistently impaired in human amnesia and animal models thereof. Results from subjects with permanent brain damage have revealed the importance of the perirhinal cortex to object recognition memory. Here, we report evidence from rats for interdependent but distinct stages in object recognition memory (encoding, retrieval, and consolidation), which require glutamate receptor activity within perirhinal cortex. Transient blockade of AMPA receptor-mediated synaptic transmission within perirhinal cortex disrupted encoding for short- and long-term memory as well as retrieval and consolidation. In contrast, transient NMDA receptor blockade during encoding affected only long-term object recognition memory; NMDA receptor activity was also necessary for consolidation but not retrieval. These results further demonstrate the importance of perirhinal cortex for object recognition memory and suggest that, as in the hippocampus, AMPA and NMDA receptors mediate synaptic transmission and activity-dependent synaptic plasticity, respectively, in several stages of memory processing

Transient inactivation of perirhinal cortex disrupts encoding, retrieval, and consolidation of object recognition memory.

Damage to perirhinal cortex (PRh) impairs object recognition memory in humans, monkeys, and rats when tested in tasks such as delayed nonmatching to sample, visual paired comparison, and its rodent analog, the spontaneous object recognition task. In the present study, we have capitalized on the discrete one-trial nature of the spontaneous object recognition task to investigate the role of PRh in several distinct stages of object recognition memory. In a series of experiments, transient inactivation of PRh was accomplished with bilateral infusions of lidocaine directly into PRh immediately before the sample phase (encoding), immediately before the choice phase (retrieval), or within the retention delay after the sample phase (storage-consolidation). Compared with performance on trials in which they received saline infusions, rats were significantly impaired when lidocaine was infused before the sample phase, regardless of the length of the retention delay. Similarly, delay-independent deficits were observed after immediate pre-choice infusions of lidocaine. Finally, PRh inactivation immediately and 20 min after the sample phase, but not 40, 60, or 80 min after, also disrupted subsequent object recognition when the retention delay was sufficiently long to ensure the dissipation of the actions of lidocaine during the choice phase. The effects of pre-sample and pre-choice inactivation indicate involvement of PRh in encoding and retrieval stages of object recognition, and the time course of post-sample inactivation effects suggests a role for PRh in the maintenance of the object trace during memory consolidation

MOVEMENT VARIABILITY IN THE SPINAL KINEMATICS OF FAST BOWLERS

The purpose of this study was to quantify the inter- and intra-individual spinal movement variability in a group of pre-elite and elite fast bowlers. Eleven pre-elite and elite level bowlers from the Otago region (New Zealand) took part in the study. Each bowler bowled two six-over spells, while being recorded by a 3D motion analysis system in two sessions, one week apart. Thorax and lumbopelvis segments were modelled and analysed. Between session changes in spine kinematics were greatest for lateral bending (p = .0001). Inter-individual variability was much greater than the average within-participant variability (more than double), highlighting the need for individual analyses of fast bowlers in the future. Inter- and intra-individual variability in spinal movement among a homogenous group of fast bowlers found in the current study will be important for designing future studies on cricket fast bowlers

Paradoxical facilitation of object recognition memory after infusion of scopolamine into perirhinal cortex: implications for cholinergic system function.

The cholinergic system has long been implicated in learning and memory, yet its specific function remains unclear. In the present study, we investigated the role of cortical acetylcholine in a rodent model of declarative memory by infusing the cholinergic muscarinic receptor antagonist scopolamine into the rat perirhinal cortex during different stages (encoding, storage/consolidation, and retrieval) of the spontaneous object recognition task. Presample infusions of scopolamine significantly impaired object recognition compared with performance of the same group of rats on saline trials; this result is consistent with previous reports supporting a role for perirhinal acetylcholine in object information acquisition. Scopolamine infusions directly before the retrieval stage had no discernible effect on object recognition. However, postsample infusions of scopolamine with sample-to-infusion delays of up to 20 h significantly facilitated performance relative to postsample saline infusion trials. Additional analysis suggested that the infusion episode could cause retroactive or proactive interference with the sample object trace and that scopolamine blocked the acquisition of this interfering information, thereby facilitating recognition memory. This is, to our knowledge, the first example of improved recognition memory after administration of scopolamine. The overall pattern of results is inconsistent with a direct role for cortical acetylcholine in declarative memory consolidation or retrieval. Rather, the cholinergic input to the perirhinal cortex may facilitate acquisition by enhancing the cortical processing of incoming stimulus information

Decision Making in Mice During an Optimized Touchscreen Spatial Working Memory Task Sensitive to Medial Prefrontal Cortex Inactivation and NMDA Receptor Hypofunction

Working memory is a fundamental cognitive process for decision-making and is a hallmark impairment in a variety of neuropsychiatric and neurodegenerative diseases. Spatial working memory paradigms are a valuable tool to assess these processes in rodents and dissect the neurobiology underlying working memory. The trial unique non-match to location (TUNL) task is an automated touchscreen paradigm used to study spatial working memory and pattern separation processes in rodents. Here, animals must remember the spatial location of a stimulus presented on the screen over a delay period; and use this representation to respond to the novel location when the two are presented together. Because stimuli can be presented in a variety of spatial configurations, TUNL offers a trial-unique paradigm, which can aid in combating the development of unwanted mediating strategies. Here, we have optimized the TUNL protocol for mice to reduce training time and further reduce the potential development of mediating strategies. As a result, mice are able to accurately perform an enhanced trial-unique paradigm, where the locations of the sample and choice stimuli can be presented in any configuration on the screen during a single session. We also aimed to pharmacologically characterize this updated protocol, by assessing the roles of the medial prefrontal cortex (mPFC) and N-methyl-D-aspartate (NMDA) receptor (NMDAr) functioning during TUNL. Temporary inactivation of the medial prefrontal cortex (mPFC) was accomplished by directly infusing a mixture of GABA agonists muscimol and baclofen into the mPFC. We found that mPFC inactivation significantly impaired TUNL performance in a delay-dependent manner. In addition, mPFC inactivation significantly increased the susceptibility of mice to proactive interference. Mice were then challenged with acute systemic injections of the NMDAr antagonist ketamine, which resulted in a dose-dependent, delay-dependent working memory impairment. Together, we describe an optimized automated touchscreen task of working memory, which is dependent on the intact functioning of the mPFC and sensitive to acute NMDAr hypofunction. With the vast genetic toolbox available for modeling disease and probing neural circuit functioning in mice, the TUNL task offers a valuable paradigm to pair with these technologies to further investigate the processes underlying spatial working memory