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An alternate derivation of Padmanabhan's differential bulk-surface relation in General Relativity
Dennis G. Smoot
Physics , 2012,
Abstract: A differential bulk-surface relation of the lagrangian of General Relativity has been derived by Padmanabhan. This has relevance to gravitational information and degrees of freedom. An alternate derivation is given based on the differential form gauge theory formulation of gravity due to Gockeler and Schucker. Also an entropy functional of Padmanabhan and Paranjape can be rewritten as the Gockeler and Schucker lagrangian.
The ‘Influenza’ Vaccine Used during the Samoan Pandemic of 1918
G. Dennis Shanks
- , 2018, DOI: 10.3390/tropicalmed3010017
Abstract:
Malaria Death in an Isolated Island Garrison on New Guinea 1915
G. Dennis Shanks
- , 2016, DOI: 10.3390/tropicalmed1010002
Abstract:
The ‘Influenza’ Vaccine Used during the Samoan Pandemic of 1918
G. Dennis Shanks
- , 2018, DOI: https://doi.org/10.3390/tropicalmed3010017
Abstract: Abstract In 1918, a crude influenza vaccine made from chemically inactivated, mixed cultures of respiratory bacteria was widely used prior to the understanding that influenza was caused by a virus. Such vaccines contained no viral material and probably consisted largely of bacterial endotoxin. The Australian military used such a vaccine on Samoa in December 1918 and thought it was valuable. Post hoc analyses suggest that the mixed respiratory bacteria vaccine may have actually been of some benefit, but the mechanism of such protection is unknown. Although such a crude vaccine would not be considered in a modern setting, the rapid use of problematic vaccines still remains a risk when new influenza types suddenly appear, as in 1976 and 2009. View Full-Tex
Layered circle packings
David Dennis,G. Brock Williams
International Journal of Mathematics and Mathematical Sciences , 2005, DOI: 10.1155/ijmms.2005.2429
Abstract: Given a bounded sequence of integers {d0,d1,d2,…}, 6≤dn≤M, there is an associated abstract triangulation created by building up layers of vertices so that vertices on the nth layer have degree dn. This triangulation can be realized via a circle packing which fills either the Euclidean or the hyperbolic plane. We give necessary and sufficient conditions to determine the type of the packing given the defining sequence {dn}.
A swimming robot actuated by living muscle tissue
Hugh Herr, Robert G Dennis
Journal of NeuroEngineering and Rehabilitation , 2004, DOI: 10.1186/1743-0003-1-6
Abstract: Many technological barriers exist for the implementation of life-like mobility in robotic and prosthetic systems. Included among these barriers are (1) the availability of high-energy density storage media, (2) the availability of adequate muscle-like actuators, and (3) the availability of biologically inspired sensory technologies. As a possible resolution to these challenges, we consider in this investigation the use of living muscle tissue as a viable actuator for synthetic devices.Although important research has been conducted to advance a synthetic actuator technology with muscle-like properties, engineering science has not yet produced a motor system that can mimic the contractility, energetics, scalability and plasticity of living muscle tissue [1,2]. Muscle has several important advantages in addition to favorable dynamic characteristics [1-6]. In its function as a motor, muscle acts to provide positive mechanical work at a considerable aerobic transduction efficiency, or 1000 Joules of work per gram of glucose consumed [7]. It is a "smart material", having integrated sensors for the detection of displacement and rate of displacement (muscle spindles) as well as force (Golgi tendon organs). It can repair itself when damaged, and can functionally adapt to an increase in the demands of the environment by undergoing hypertrophic and hyperplastic growth [8] as well as fiber type transformations [9-12]. Muscle has integrated series-elastic components, which are thought to give rise to many of the "life-like" characteristics of animal movement [13], and the fuel that it consumes is a renewable resource, while the waste products produced are environmentally compatible.In this investigation, we examine the feasibility of using animal-derived muscle as an actuator for artificial devices in the millimeter to centimeter size scale. Perhaps researchers in the past did not consider muscle tissue a viable mechanical actuator because of tissue maintenance and control diffi
Molecular Codes in Biological and Chemical Reaction Networks
Dennis G？rlich, Peter Dittrich
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054694
Abstract: Shannon’s theory of communication has been very successfully applied for the analysis of biological information. However, the theory neglects semantic and pragmatic aspects and thus cannot directly be applied to distinguish between (bio-) chemical systems able to process “meaningful” information from those that do not. Here, we present a formal method to assess a system’s semantic capacity by analyzing a reaction network’s capability to implement molecular codes. We analyzed models of chemical systems (martian atmosphere chemistry and various combustion chemistries), biochemical systems (gene expression, gene translation, and phosphorylation signaling cascades), an artificial chemistry, and random reaction networks. Our study suggests that different chemical systems posses different semantic capacities. No semantic capacity was found in the model of the martian atmosphere chemistry, the studied combustion chemistries, and highly connected random networks, i.e. with these chemistries molecular codes cannot be implemented. High semantic capacity was found in the studied biochemical systems and in random reaction networks where the number of second order reactions is twice the number of species. We conclude that our approach can be applied to evaluate the information processing capabilities of a chemical system and may thus be a useful tool to understand the origin and evolution of meaningful information, e.g. in the context of the origin of life.
Somatosensory Information Processing in the Aging Population
Robert G. Dennis,Mark Tommerdahl
Frontiers in Aging Neuroscience , 2011, DOI: 10.3389/fnagi.2011.00018
Abstract: While it is well known that skin physiology – and consequently sensitivity to peripheral stimuli – degrades with age, what is less appreciated is that centrally mediated mechanisms allow for maintenance of the same degree of functionality in processing these peripheral inputs and interacting with the external environment. In order to demonstrate this concept, we obtained observations of processing speed, sensitivity (thresholds), discriminative capacity, and adaptation metrics on subjects ranging in age from 18 to 70. The results indicate that although reaction speed and sensory thresholds change with age, discriminative capacity, and adaptation metrics do not. The significance of these findings is that similar metrics of adaptation have been demonstrated to change significantly when the central nervous system (CNS) is compromised. Such compromise has been demonstrated in subject populations with autism, chronic pain, acute NMDA receptor block, concussion, and with tactile–thermal interactions. If the metric of adaptation parallels cortical plasticity, the results of the current study suggest that the CNS in the aging population is still capable of plastic changes, and this cortical plasticity could be the mechanism that compensates for the degradations that are known to naturally occur with age. Thus, these quantitative measures – since they can be obtained efficiently and objectively, and appear to deviate from normative values significantly with systemic cortical alterations – could be useful indicators of cerebral cortical health.
Molecular Codes in Biological and Non-Biological Reaction Networks
Dennis G？rlich,Peter Dittrich
Quantitative Biology , 2011,
Abstract: Can we objectively distinguish chemical systems that are able to process meaningful information from those that are not suitable for information processing? Here, we present a formal method to assess the semantic capacity of a chemical reaction network. The semantic capacity of a network can be measured by analyzing the capability of the network to implement molecular codes. We analyzed models of real chemical systems (Martian atmosphere chemistry and various combustion chemistries), bio-chemical systems (gene expression, gene translation, and phosphorylation signaling cascades), as well as an artificial chemistry and random networks. Our study suggests that different chemical systems posses different semantic capacities. Basically no semantic capacity was found in the atmosphere chemistry of Mars and all studied combustion chemistries, as well as in highly connected random networks, i.e., with these chemistries molecular codes cannot be implemented. High semantic capacity was found in the bio-chemical systems, as well as in random networks where the number of second order reactions is at the number of species. Hypotheses concern the origin and evolution of life. We conclude that our approach can be applied to evaluate the information processing capabilities of a chemical system and may thus be a useful tool to understand the origin and evolution of meaningful information, e.g., at the origin of life.
Influenza Before the 1890 and 1918 Pandemics in the US Army and at the US Military Academy
G Dennis Shanks,Melissa Eslinger
- , 2019, DOI: 10.1093/ofid/ofz207
Abstract: Influenza rates for the US Army and West Point cadets showed that seasonal influenza was not necessarily an annual event, and there was little influenzal illness in the decade before 1918 except for 1911 and 1916. Annual records from 1862–1918 also indicated a similar paucity of influenzal illness before 1890
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