On the Lyapunov Matrix of Linear Delay Difference Equations in Continuous Time

The fundamental matrix and the delay Lyapunov matrix of linear delay difference equations are introduced. Some properties of the Lyapunov matrix, and the jump discontinuities of its derivative are proven, leading to its construction in the case of single delay or commensurate delays. An approximation is proposed for the non-commensurate case

YZ250 LHRB

YZ250 LHRB A Left Hand Rear Brake (LHRB) means that a motorcycle can not only have the rear brake operated by the foot pedal that comes standard on all bikes, but it can be actuated by a lever located on the handlebar as well. The purpose of this engineering project is to design a bracket that can hold two brake calipers while not hindering stock handling. It should also add braking usability and power. The device is to be made of mild steel for the first models, this will allow for ease of prototyping, fitment testing, and finalized design testing. The bracket needs to be functional, holding two brake calipers, be crash resistant and resistant to the elements. The testing methods will be both in the field and in the lab. It will be bench tested for weight and deflection requirements. Then it will be tested in real world situations to see how well it will hold up in maximum conditions. The predicted results of the steel version of the bracket is to be: 1) The device should not weigh more than 150% of the original bracket for a single brake caliper. 2) No arm of the bracket should deflect more than ten-thousands of an inch under the maximum braking force. 3) The brake lever should be able to complete a full lock of up the rear brakes with a 10lb force pull on the hand lever. After testing sequences are completed an aluminum version is the end goal of the project. Keywords

Comparing Stress Responses in Generalized Anxiety Disorder vs. Non-Clinical Populations: A Cortisol and Alpha-Amylase Study

Debilitating anxiety affects 6.8 million Americans. Cortisol is an established measure of the stress response which reflects the hypothalamic-pituitary-adrenal (HPA) axis activity. However, salivary alpha-amylase (sAA) is a relatively new measure of the stress response, and it reflects the sympathetic-adrenal-medullary pathway (SAM pathway) activity. Our aim was to compare these two aspects of the stress response in a Generalized Anxiety Disorder (GAD) and a non-clinical population under a stressful stimulus (Knee replacement surgery video). To our knowledge this is the first time anyone has looked at both sAA and cortisol together with respect to GAD. We hypothesized that both cortisol and sAA levels would raise from pre-stimulus to post-stimulus, but not in concert. Forty-six college students were assessed for GADs and randomly assigned to watch a stressful or neutral video. Saliva samples were taken at the beginning of the study, immediately after the video, and 30 minutes after the video. Participants were also given the Taylor Manifest Anxiety Scale TMAS and Beck Anxiety Inventory BAI as measures of state and trait anxiety. There was a significant difference between GAD and non-clinical groups for the TMAS and a significant group by condition interaction for baseline cortisol. Our GAD, stress sub-group had a significantly raised baseline cortisol level. Although the GAD and Non-clinical groups did not differ significantly with regard to baseline cortisol levels, it was in the hypothesized direction. Moreover, baseline cortisol levels were inversely related to baseline sAA levels. The findings suggest that cortisol and sAA show contrary diurnal responses

Predator and detritivore niche width helps to explain biocomplexity of experimental detritus-based food webs in four aquatic and terrestrial ecosystems

In the study of food webs, the existence and explanation of recurring patterns, such as the scale invariance of linkage density, predator–prey ratios and mean chain length, constitute long-standing issues. Our study focused on litter-associated food webs and explored the influence of detritivore and predator niche width (as d13C range) on web topological structure. To compare patterns within and between aquatic and terrestrial ecosystems and take account of intra-habitat variability, we constructed 42 macroinvertebrate patch-scale webs in four different habitats (lake, lagoon, beech forest and cornfield), using an experimental approach with litterbags. The results suggest that although web differences exist between ecosystems, patterns are more similar within than between aquatic and terrestrial web types. In accordance with optimal foraging theory, we found that the niche width of predators and prey increased with the number of predators and prey taxa as a proportion of total taxa in the community. The tendency was more marked in terrestrial ecosystems and can be explained by a lower per capita food level than in aquatic ecosystems, particularly evident for predators. In accordance with these results, the number of links increased with the number of species but with a significantly sharper regression slope for terrestrial ecosystems. As a consequence, linkage density, which was found to be directly correlated to niche width, increased with the total number of species in terrestrial webs, whereas it did not change significantly in aquatic ones, where connectance scaled negatively with the total number of species. In both types of ecosystem, web robustness to rare species removal increased with connectance and the niche width of predators. In conclusion, although limited to litter-associated macroinvertebrate assemblages, this study highlights structural differences and similarities between aquatic and terrestrial detrital webs, providing field evidence of the central role of niche width in determining the structure of detritus-based food webs and posing foraging optimisation constraints as a general mechanistic explanation of food web complexity differences within and between ecosystem types

Josef Hoffmann e il sanatorio di Purkersdorf

É chiaro che il Mediterraneo è cosa complessa e sfaccettata, disponibile ad alimentare, ricevere e generare tutta una serie di pensieri ed elaborazioni. La proposta si avvale dell’interpretazione progettuale che architetti non appartenenti alla cultura mediterranea danno del Mediterraneo. Si tratta di una dimostrazione per assurdo che va a ricercare un agente tracciante esaminando esperienze di qualcuno che ha dovuto elaborare un concetto che per noi è familiare. Essi hanno avvertito la necessità di porsi una domanda: “che cosa è il Mediterraneo?” L’operazione, dunque, consiste nella decodificazione di un codice scaturito da architetti non appartenenti geograficamente alla mediterraneità. Ciò che questi architetti ricercano è la costruzione di un’idea di spazio che hanno potuto esperire nel grand tour. Il viaggio in Italia rappresenta un viaggio nella memoria. La ricerca attraverso l’esperienza di un’architettura costruita nell’intelletto attraverso il mito. La ricerca della costruzione di un’idea. I giovani del nord scendono al sud per esperire l’archè, per ritrovare o trovare l’immagine primordiale dell’architetture, l’ordine universale, l’archetipo da cui tutto ha avuto inizio e per comprenderne la technè, ovvero i tipi e i modi della costruzione. Un protagonista del viaggio attraverso il Mediterraneo è l’architetto Austriaco J. Hoffmann, testimoniato da una serie di immagini ed elaborazioni grafiche che assumeranno un bagaglio importante nella sua attività progettuale. La conferma sul ruolo decisivo giocato dall’Italienische Reise nella sua formazione trova il suo apice nella pura stereometria del Sanatorio di Punkersdorf a Vienna, in qui il linguaggio hauffmanniano raccoglie i risultati del processo di decantazione delle immagini contemplate durante il suo viaggio al sud. Già tra pagine di Der Architekt, nel suo scritto L’architettura dell’Isola di Capri, si trova traccia del valore che per l’austriaco assume la ricerca architettonica indirizzata verso la mediterraneità. L’obiettivo è quello di rintracciare un fil rouge che lega le immagini del grand tour di Hoffmann e le sue realizzazioni da architetto. La forza della ricerca portata avanti da questo architetto è osservare, comprendere e riprodurre criticamente un’idea, trasformandola in un’idea costruita

Renal lesions in patients with type 2 diabetes: A puzzle waiting to be solved

Three hundred sixty-six million people worldwide will be living with diabetes mellitus (DM) by 2030 ([1, 2]; http://www.idf.org/global-diabetes-plan-2011-2021). Prospectively, 75–150 million of these patients will develop a diabetic nephropathy (DN) or a non-diabetic renal disease (NDRD), either isolated or superimposed on DN [3, 4]. To date, the differential diagnosis between ND and NDRD remains a challenge that nephrologists are trying to win [5]