Darkness Alters Maturation of Visual Cortex and Promotes Fast Recovery from Monocular Deprivation

SummaryThe existence of heightened brain plasticity during critical periods in early postnatal life is a central tenet of developmental sensory neuroscience and helps explain the enduring deficits induced by early abnormal sensory exposure [1, 2]. The human visual disorder amblyopia has been linked to unbalanced visual input to the two eyes in early postnatal visual cortical development and has been modeled in animals by depriving them of patterned visual input to one eye [3, 4], a procedure known as monocular deprivation (MD). We investigated the possibility that a period of darkness might reset the central visual pathways to a more plastic stage and hence increase the capacity for recovery from early MD. Here we show that a 10 day period of complete darkness reverses maturation of stable cytoskeleton components in kitten visual cortex and also results in rapid elimination of, or even immunity from, visual deficits linked to amblyogenic rearing by MD. The heightened instability of the cytoskeleton induced by darkness likely represents just one of many parallel molecular changes that promote visual recovery, possibly by release of the various brakes on cortical plasticity [2]

Serious Economic Pests of Coffee That May Accidentally be Introduced to Hawai'i

The purpose of this publication is to provide information about serious diseases and pests of coffee not present in the Hawaiian Islands that can be accidentally introduced on or in coffee berries brought in for seed purposes. Particularly, we focus on those diseases and pests that could be a threat to coffee production in Hawai'i. The publication is designed to serve as a reference for growers, county agents, consultants, researchers, and quarantine personnel

Recovery of neurofilament following early monocular deprivation

Postnatal development of the mammalian geniculostriate visual pathway is partly guided by visually driven activity. Disruption of normal visual input during certain critical periods can alter the structure of neurons, as well as their connections and functional properties. Within the layers of the dorsal lateral geniculate nucleus (dLGN), a brief early period of monocular deprivation can alter the structure and soma size of neurons within deprived-eye-receiving layers. This modification of structure is accompanied by a marked reduction in labeling for neurofilament protein, a principle component of the stable cytoskeleton. This study examined the extent of neurofilament recovery in monocularly deprived cats that either had their deprived eye opened (binocular recovery), or had the deprivation reversed to the fellow eye (reverse occlusion). The loss of neurofilament and the reduction of soma size caused by monocular deprivation were ameliorated equally and substantially in both recovery conditions after 8 days. The degree to which this recovery was dependent on visually driven activity was examined by placing monocularly deprived animals in complete darkness. Though monocularly deprived animals placed in darkness showed recovery of soma size in deprived layers, the manipulation catalyzed a loss of neurofilament labeling that extended to non-deprived layers as well. Overall, these results indicate that both recovery of soma size and neurofilament labeling is achieved by removal of the competitive disadvantage of the deprived eye. However, while the former occurred even in the absence of visually driven activity, recovery of neurofilament did not. The finding that a period of darkness produced an overall loss of neurofilament throughout the dLGN suggests that this experiential manipulation may cause the visual pathways to revert to an earlier more plastic developmental stage. It is possible that short periods of darkness could be incorporated as a component of therapeutic measures for treatment of deprivation-induced disorders such as amblyopia

Oxygen ion dynamics in the Earth's ring current: Van Allen probes observations

Oxygen (O+) enhancements in the inner magnetosphere are often observed during geomagnetically active times, such as geomagnetic storms. In this study, we quantitatively examine the difference in ring current dynamics with and without a substantial O+ ion population based on almost 6 years of Van Allen Probes observations. Our results have not only confirmed previous finding of the role of O+ ions to the ring current but also found that abundant O+ ions are always present during large storms when sym-H < -60 nT without exception, whilst having the pressure ratio () between O+ and proton (H+) larger than 0.8 and occasionally even larger than 1 when L < 3. Simultaneously, the pressure anisotropy decreases with decreasing sym-H and increasing L shell. The pressure anisotropy decrease during the storm main phase is likely related to the pitch angle isotropization processes. In addition, we find that increases during the storm main phase and then decreases during the storm recovery phase, suggesting faster buildup and decay of O+ pressure compared to H+ ions, which are probably associated with some species dependent source and/or energization as well as loss processes in the inner magnetosphere.Accepted manuscrip

The Permanence of the Visual Recovery that Follows Reverse Occlusion of Monocularly Deprived Kittens

While the behavioral and physiologic effects of an early period of monocular deprivation can be extremely severe, they are not necessarily irreversible. Considerable recovery can occur if visual input is restored to the deprived eye sufficiently early, particularly if the nondeprived eye is occluded at the same time (reverse occlusion). This study examines the permanence of the visual recovery promoted by a period of reverse occlusion in kittens that were monocularly deprived from near birth for periods ranging from 3 to 18 weeks. During the period of reverse occlusion, the vision of the initially deprived eye improved from apparent blindness to good levels of acuity. However, upon restoring visual input to the formerly nondeprived eye a surprisingly rapid and reciprocal change occurred in the visual acuity of both eyes. Much of the substantial gain in the vision of the initially deprived eye that occurred during reverse occlusion was lost within 3 weeks, while at the same time the vision of the initially nondeprived eye improved substantially. Nevertheless, in many animals the acuity of the initially nondeprived eye did not recover to levels it had reached prior to reverse occlusion. These results hold important implications for the nature of the mechanisms responsible for the dramatic physiologic effects of monocular occlusion and reverse occlusion on the visual cortex. The results also may help elucidate recent observations on patching therapy in human amblyopia. Invest Ophthalmol Vis Sci 25: [908][909][910][911][912][913][914][915][916][917] 1984 The behavioral and physiologic consequences of early monocular deprivation by eyelid closure have been explored extensively in both cats and monkeys

An algorithmic and information-theoretic approach to multimetric index construction

The use of multimetric indices (MMIs), such as the widely used index of biological integrity (IBI), to measure, track, summarize and infer the overall impact of human disturbance on biological communities has been steadily growing in recent years. Initially, MMIs were developed for aquatic communities using preselected biological metrics as indicators of system integrity. As interest in these bioassessment tools has grown, so have the types of biological systems to which they are applied. For many ecosystem types the appropriate biological metrics to use as measures of biological integrity are not known a priori. As a result, a variety of ad hoc protocols for selecting metrics empirically has developed. However, the assumptions made by proposed protocols have not be explicitly described or justified, causing many investigators to call for a clear, repeatable methodology for developing empirically derived metrics and indices that can be applied to any biological system. An issue of particular importance that has not been sufficiently addressed is the way that individual metrics combine to produce an MMI that is a sensitive composite indicator of human disturbance. In this paper, we present and demonstrate an algorithm for constructing MMIs given a set of candidate metrics and a measure of human disturbance. The algorithm uses each metric to inform a candidate MMI, and then uses information-theoretic principles to select MMIs that capture the information in the multidimensional system response from among possible MMIs. Such an approach can be used to create purely empirical (data-based) MMIs or can, optionally, be influenced by expert opinion or biological theory through the use of a weighting vector to create value-weighted MMIs. We demonstrate the algorithm with simulated data to demonstrate the predictive capacity of the final MMIs and with real data from wetlands from Acadia and Rocky Mountain National Parks. For the Acadia wetland data, the algorithm identified 4 metrics that combined to produce a −0.88 correlation with the human disturbance index. When compared to other methods, we find this algorithmic approach resulted in MMIs that were more predictive and comprise fewer metrics

The complete management of extremity vascular injury in a local population: A wartime report from the 332nd Expeditionary Medical Group/Air Force Theater Hospital, Balad Air Base, Iraq

Background: Although the management of vascular injury in coalition forces during Operation Iraqi Freedom has been described, there are no reports on the in-theater treatment of wartime vascular injury in the local population. This study reports the complete management of extremity vascular injury in a local wartime population and illustrates the unique aspects of this cohort and management strategy. Methods: From September 1, 2004, to August 31, 2006, all vascular injuries treated at the Air Force Theater Hospital (AFTH) in Balad, Iraq, were registered. Those in non-coalition troops were identified and retrospectively reviewed. Results: During the study period, 192 major vascular injuries were treated in the local population in the following distribution: extremity 70% (n = 134), neck and great vessel 17% (n = 33), and thoracoabdominal 13% (n = 25). For the extremity cohort, the age range was 4 to 68 years and included 12 pediatric injuries. Autologous vein was the conduit of choice for these vascular reconstructions. A strict wound management strategy providing repeat operative washout and application of the closed negative pressure adjunct was used. Delayed primary closure or secondary coverage with a split-thickness skin graft was required in 57% of extremity wounds. All patients in this cohort remained at the theater hospital through definitive wound healing, with an average length of stay of 15 days (median 11 days). Patients required an average of 3.3 operations (median 3) from the initial injury to definitive wound closure. Major complications in extremity vascular patients, including mortality, were present in 15.7% (n = 21). Surgical wound infection occurred in 3.7% (n = 5), and acute anastomotic disruption in 3% (n = 4). Graft thrombosis occurred in 4.5% (n = 6), and early amputation and mortality rates during the study period were 3.0% (n = 4) and 1.5% (n = 2), respectively. Conclusions: To our knowledge, this study represents the first large report of wartime extremity vascular injury management in a local population. These injuries present unique challenges related to complex wounds that require their complete management to occur in-theater. Vascular reconstruction using vein, combined with a strict wound management strategy, results in successful limb salvage with remarkably low infection, amputation and mortality rates

The Development and Use of an Innovative Laboratory Method for Measuring Arsenic in Drinking Water from Western Bangladesh

All of Bangladesh’s approximately 10 million drinking-water tube wells must be periodically tested for arsenic. The magnitude of this task and the limited resources of Bangladesh have led to the use of low-cost, semiquantitative field kits that measure As to a relatively high 50 μg/L national drinking water standard. However, there is an urgent need to supplement and ultimately replace these field kits with an inexpensive laboratory method that can measure As to the more protective 10 μg/L World Health Organization (WHO) health-based drinking water guideline. Unfortunately, Bangladesh has limited access to atomic absorption spectrometers or other expensive instruments that can measure As to the WHO guideline of 10 μg/L. In response to this need, an inexpensive and highly sensitive laboratory method for measuring As has been developed. This new method is the only accurate, precise, and safe way to quantify As < 10 μg/L without expensive or highly specialized laboratory equipment. In this method, As is removed from the sample by reduction to arsine gas, collected in an absorber by oxidation to arsenic acid, colorized by a sequential reaction to arsenomolybdate, and quantified by spectrophotometry. We compared this method with the silver diethyldithiocarbamate [AgSCSN(CH(2)CH(3))(2)] and graphite furnace atomic absorption spectroscopy (GFAAS) methods for measuring As. Our method is more accurate, precise, and environmentally safe than the AgSCSN(CH(2)CH(3))(2) method, and it is more accurate and affordable than GFAAS. Finally, this study suggests that Bangladeshis will readily share drinking water with their neighbors to meet the more protective WHO guideline for As of 10 μg/L

Artificial Stupidity

Public debate about AI is dominated by Frankenstein Syndrome, the fear that AI will become superhuman and escape human control. Although superintelligence is certainly a possibility, the interest it excites can distract the public from a more imminent concern: the rise of Artificial Stupidity (AS). This article discusses the roots of Frankenstein Syndrome in Mary Shelley’s famous novel of 1818. It then provides a philosophical framework for analysing the stupidity of artificial agents, demonstrating that modern intelligent systems can be seen to suffer from ‘stupidity of judgement’. Finally it identifies an alternative literary tradition that exposes the perils and benefits of AS. In the writings of Edmund Spenser, Jonathan Swift and E.T.A. Hoffmann, ASs replace, enslave or delude their human users. More optimistically, Joseph Furphy and Laurence Sterne imagine ASs that can serve human intellect as maps or as pipes. These writers provide a strong counternarrative to the myths that currently drive the AI debate. They identify ways in which even stupid artificial agents can evade human control, for instance by appealing to stereotypes or distancing us from reality. And they underscore the continuing importance of the literary imagination in an increasingly automated society