Environmental Enrichment Induces Behavioral Recovery and Enhanced Hippocampal Cell Proliferation in an Antidepressant-Resistant Animal Model for PTSD

Background: Post traumatic stress disorder (PTSD) can be considered the result of a failure to recover after a traumatic experience. Here we studied possible protective and therapeutic aspects of environmental enrichment (with and without a running wheel) in Sprague Dawley rats exposed to an inescapable foot shock procedure (IFS). Methodology/Principal Findings: IFS induced long-lasting contextual and non-contextual anxiety, modeling some aspects of PTSD. Even 10 weeks after IFS the rats showed reduced locomotion in an open field. The antidepressants imipramine and escitalopram did not improve anxiogenic behavior following IFS. Also the histone deacetylase (HDAC) inhibitor sodium butyrate did not alleviate the IFS induced immobility. While environmental enrichment (EE) starting two weeks before IFS did not protect the animals from the behavioral effects of the shocks, exposure to EE either immediately after the shock or one week later induced complete recovery three weeks after IFS. In the next set of experiments a running wheel was added to the EE to enable voluntary exercise (EE/VE). This also led to reduced anxiety. Importantly, this behavioral recovery was not due to a loss of memory for the traumatic experience. The behavioral recovery correlated with an increase in cell proliferation in hippocampus, a decrease in the tissue levels of noradrenalin and increased turnover of 5-HT in prefrontal cortex and hippocampus. Conclusions/Significance: This animal study shows the importance of (physical) exercise in the treatment of psychiatri

New insights from a structural economic dynamic approach to balance of payments constrained growth

In this paper it is shown that once-for-all variations in the level of the exchange rate may play an important role in the sectoral composition of the economy and this fact has important implications in terms of a disaggregated version of the Thirlwall’s law even if the argument of the quantitative unimportance of relative price movements holds. The growth rate of a country is then shown to be affected by once-for-all movements in the level of nominal exchange rates and the concept of a natural exchange rate is introduced

Economic Analysis of Knowledge: The History of Thought and the Central Themes

Following the development of knowledge economies, there has been a rapid expansion of economic analysis of knowledge, both in the context of technological knowledge in particular and the decision theory in general. This paper surveys this literature by identifying the main themes and contributions and outlines the future prospects of the discipline. The wide scope of knowledge related questions in terms of applicability and alternative approaches has led to the fragmentation of research. Nevertheless, one can identify a continuing tradition which analyses various aspects of the generation, dissemination and use of knowledge in the economy

Cross-education does not accelerate the rehabilitation of neuromuscular functions after ACL reconstruction: a randomized controlled clinical trial

Purpose: Cross-education reduces quadriceps weakness 8 weeks after anterior cruciate ligament (ACL) surgery, but the long-term effects are unknown. We investigated whether cross-education, as an adjuvant to the standard rehabilitation, would accelerate recovery of quadriceps strength and neuromuscular function up to 26 weeks post-surgery. Methods: Group allocation was randomized. The experimental (n = 22) and control (n = 21) group received standard rehabilitation. In addition, the experimental group strength trained the quadriceps of the non-injured leg in weeks 1–12 post-surgery (i.e., cross-education). Primary and secondary outcomes were measured in both legs 29 ± 23 days prior to surgery and at 5, 12, and 26 weeks post-surgery. Results: The primary outcome showed time and cross-education effects. Maximal quadriceps strength in the reconstructed leg decreased 35% and 12% at, respectively, 5 and 12 weeks post-surgery and improved 11% at 26 weeks post-surgery, where strength of the non-injured leg showed a gradual increase post-surgery up to 14% (all p ≤ 0.015). Limb symmetry deteriorated 9–10% more for the experimental than control group at 5 and 12 weeks post-surgery (both p ≤ 0.030). One of 34 secondary outcomes revealed a cross-education effect: Voluntary quadriceps activation of the reconstructed leg was 6% reduced for the experimental vs. control group at 12 weeks post-surgery (p = 0.023). Both legs improved force control (22–34%) and dynamic balance (6–7%) at 26 weeks post-surgery (all p ≤ 0.043). Knee joint proprioception and static balance remained unchanged. Conclusion: Standard rehabilitation improved maximal quadriceps strength, force control, and dynamic balance in both legs relative to pre-surgery but adding cross-education did not accelerate recovery following ACL reconstruction

Simplistic vs. Complex Organization: Markets, Hierarchies, and Networks in an 'Organizational Triangle'

Transaction cost economics explains organizations in a simplistic ‘market-vs.-hierarchy’ dichotomy. In this view, complex real-world coordination forms are simply considered ‘hybrids’ of those ‘pure’ and ideal forms, thus being located on a one-dimensional ‘line’ between them. This ‘organizational dichotomy’ is mainly based on relative marginal transaction costs, relative lengths of value-added chains, and ‘rational choice’ of coordination form. The present paper, in contrast, argues that pure ‘market’ and ‘hierarchy’, even including their potential hybrids, are a theoretically untenable and empirically void set. Coordination forms, it is argued, have to be conceptualized in a fundamentally different way. A relevant ‘organizational space’ must reflect the dimensions of a complex world such as dilemma-prone direct interdependence, resulting in strong strategic uncertainty, mutual externalities, collectivities, and subsequent emergent process. This, in turn, will lead either to (1) informally institutionalized, problem-solving cooperation (the instrumental dimension of the institution) or (2) mutual blockage, lock-in on an inferior path, or power- and status-based market and hierarchy failure (the ceremonial dimension of the institution). This paper establishes emergent instrumental institutionalized cooperation as a genuine organizational dimension which generates a third ‘attractor’ besides ‘market’ and ‘hierarchy’, i.e., informal network. In this way, an ‘organizational triangle’ can be generated which may serve as a more relevant heuristic device for empirical organizational research. Its ideal corners and some ideal hybrids on its edges (such as ideal clusters and ideal hub&spoke networks) still remain empirically void, but its inner space becomes empirically relevant and accessible. The ‘Organizational Triangle’ is tentatively applied (besides casual reference to corporate behavior that has lead to the current financial meltdown), by way of a set of criteria for instrumental problem-solving and a simple formal algorithm, to the cases of the supplier network of ‘DaimlerChrysler US International’ at Tuscaloosa, AL, the open-source network Linux, and the web-platforms Wikipedia and ‘Open-Source Car’. It is considered to properly reflect what is generally theorized in evolutionary-institutional economics of organizations and the firm and might offer some insight for the coming industrial reconstructions of the car and other industries

Rapid assessment of the tracking resistance of bituminous crack sealants

The bituminous sealants used in the preventive maintenance of pavements sometimes deform (track) under the action of passing vehicles. In summer, this is the prevalent mode of sealant failure. To assess the propensity of a sealant to deform in summer a standard flow test is used, but the imprecision in the results have prevented any correlation with field performance. In an attempt to find an alternative means of assessing deformation, two methods were evaluated. The first method relied on the use of the French rut tester, whereas the second method relied on the use of a Taber abraser. The first method was found to be inappropriate to test sealants because of its severity, but the second method proved promising. The Taber abraser allowed for the measurement of sealant displacement at various temperatures, and for distinguishing the deformation propensity of sealants.On utilise les produits de calfeutrage pour l'entretien pr\ue9ventif des chauss\ue9es. Ces produits se d\ue9forment parfois pour former des pistes sous l'action des v\ue9hicules qui circulent. Il s'agit du mode principal de d\ue9faillance de ces produits de calfeutrage en \ue9t\ue9. On utilise en g\ue9n\ue9ral un essai d'\ue9coulement normalis\ue9 pour \ue9valuer la propension d'un produit de calfeutrage \ue0 se d\ue9former en \ue9t\ue9, mais l'impr\ue9cision des r\ue9sultats emp\ueache toute corr\ue9lation avec la performance sur le terrain. On a donc \ue9valu\ue9 deux m\ue9thodes pour tenter de trouver d'autres moyens de mesurer la d\ue9formation. La premi\ue8re m\ue9thode repose sur l'utilisation de l'orni\ue9reur LPC (Laboratoire des Ponts et Chauss\ue9es), alors que la seconde m\ue9thode repose sur l'utilisation de l'abrasim\ue8tre Taber. La premi\ue8re m\ue9thode s'est av\ue9r\ue9e infructueuse pour \ue9valuer les produits de calfeutrage en raison de sa s\ue9v\ue9rit\ue9, mais la seconde m\ue9thode s'est av\ue9r\ue9e prometteuse. L'abrasim\ue8tre Taber a permis de mesurer de la d\ue9formation de produits de calfeutrage \ue0 diverses temp\ue9ratures et de distinguer la propension des produits de calfeutrage \ue0 se deformer.Peer reviewed: YesNRC publication: Ye

A biomechanical assessment of ACL injury reconstructions to examine internal tibial rotation

The Anterior Cruciate Ligament injury in the human knee joint has long been a debilitating injury, particularly amongst professional athletes, often requiring a reconstruction and an extensive rehabilitation period. Surgeons commonly use the single bundle reconstructions to replicate the biomechanical restraint and stability the ligament structure provides to the knee joint against anterior translation and excessive internal rotation of the tibia with respect to the femur. However after follow up of these patients during high demanding tasks, such as single legged landing there is still presentation of increased internal rotation at the knee and osteoarthritis 5-10 years following surgery. This suggests this surgical technique may not restore all the biomechanical support the natural ACL provides to the knee joint. The work presented here covers musculoskeletal computational modeling utilizing inverse kinematics predictions of knee rotation to calculate the internal rotation of the tibia. Using the model, gait analysis of ACL reconstructed subjects is compared with control healthy subjects to understand whether Internal Tibial Rotation (ITR) is fully restored in ACL single bundle reconstructions during a dynamic hop movement