The effects of freezing and storage time on the quality of reindeer meat

Master's Project University of Alaska Fairbanks, 2017Restaurants, wholesalers and retailers of fresh meat require a year round consistent supply of uniform quality product to sustain demand and justify niche market costs such as advertisement and stocking product. Frozen reindeer meat could be stored, short or long term to increase availability provided there are no adverse effects of freezing. No studies to date have evaluated the effects of freezing and storage time on reindeer meat quality. Nine reindeer steers (castrated bulls; age 2.5 years) were fed a balanced milled ration at the University of Alaska Fairbanks (UAF) Reindeer Research Program (RRP) facility at the Agricultural Forestry Experiment Station (AFES). In February, animals were transported to a USDA approved meat processing facility for slaughter where both striploins (M. longissimus dorsi) were removed from the carcasses. The striploin samples were allocated to four subsamples consisting of fresh (control), freshly frozen, 6 month frozen and 12 month frozen treatment groups to determine if freezing and frozen storage of reindeer meat for up to one year effects meat quality. All samples underwent shear force measurement, water holding capacity (WHC) determination, proximate analysis, sensory evaluation, TBARS (rancidity) and fatty acid methyl ester profile (FAMES) analysis. Meat was sampled after 6 months of frozen storage for amino acid and mineral analysis. Shear force values were not significantly different amongst treatment groups fresh to 12 month (P=0.992). Purge and cooking loss variation were significant between fresh and 12 months (P = 1e-05,1e-04). There was no significant difference from fresh to 12 month in moisture, ash and protein content while lipid content variation was significantly different (P = 0.99, 1.00, 1.00 and < 1e -6 respectively). Tenderness and juiciness attributes were not significantly different among treatment groups fresh and 12 month (P=0.91 and P=0.53); however, an off flavor attribute was significantly different (P=0.005) amongst treatment groups suggesting that off flavor diminishes with freezing. While not detected in sensory evaluation, mean TBARS (rancidity) values increased significantly (P = <.1e-04) between fresh and 12 months. Characterization of reindeer muscle indicated that the amino acid profile and selected mineral were consistent with that of a high quality nutritional meat product. Omega 3 fatty acid (W3), Omega 6 fatty acid (W6), Monounsaturated fatty acid (MUFA), Polyunsaturated fatty acid (PUFA), the ratio between Omega 3 and Omega 6 (W3/W6) and the ratio between PUFA and MUFA (PS) were not significantly different while Saturated fatty acid (SAFA) was significantly different amongst treatments groups from fresh to 12 months. (P= 0.35, 1.00, 0.96, 0.12, 1.00, 0.14 and 0.03). Results of this study suggest reindeer meat can be frozen for up to a year without compromising quality. This could facilitate the marketing flexibility for the reindeer industry to be able to provide a consistent supply of product year round to niche restaurants and wholesalers while commanding a premium price

Energy Dissipation Via Coupling With a Finite Chaotic Environment

We study the flow of energy between a harmonic oscillator (HO) and an external environment consisting of N two-degrees of freedom non-linear oscillators, ranging from integrable to chaotic according to a control parameter. The coupling between the HO and the environment is bilinear in the coordinates and scales with system size with the inverse square root of N. We study the conditions for energy dissipation and thermalization as a function of N and of the dynamical regime of the non-linear oscillators. The study is classical and based on single realization of the dynamics, as opposed to ensemble averages over many realizations. We find that dissipation occurs in the chaotic regime for a fairly small N, leading to the thermalization of the HO and environment a Boltzmann distribution of energies for a well defined temperature. We develop a simple analytical treatment, based on the linear response theory, that justifies the coupling scaling and reproduces the numerical simulations when the environment is in the chaotic regime.Comment: 7 pages, 10 figure

Modular structure in C. elegans neural network and its response to external localized stimuli

Synchronization plays a key role in information processing in neuronal networks. Response of specific groups of neurons are triggered by external stimuli, such as visual, tactile or olfactory inputs. Neurons, however, can be divided into several categories, such as by physical location, functional role or topological clustering properties. Here we study the response of the electric junction C. elegans network to external stimuli using the partially forced Kuramoto model and applying the force to specific groups of neurons. Stimuli were applied to topological modules, obtained by the ModuLand procedure, to a ganglion, specified by its anatomical localization, and to the functional group composed of all sensory neurons. We found that topological modules do not contain purely anatomical groups or functional classes, corroborating previous results, and that stimulating different classes of neurons lead to very different responses, measured in terms of synchronization and phase velocity correlations. In all cases, however, the modular structure hindered full synchronization, protecting the system from seizures. More importantly, the responses to stimuli applied to topological and functional modules showed pronounced patterns of correlation or anti-correlation with other modules that were not observed when the stimulus was applied to ganglia.Comment: 23 pages, 6 figure

A Structured Systems Approach for Optimal Actuator-Sensor Placement in Linear Time-Invariant Systems

In this paper we address the actuator/sensor allocation problem for linear time invariant (LTI) systems. Given the structure of an autonomous linear dynamical system, the goal is to design the structure of the input matrix (commonly denoted by $B$) such that the system is structurally controllable with the restriction that each input be dedicated, i.e., it can only control directly a single state variable. We provide a methodology that addresses this design question: specifically, we determine the minimum number of dedicated inputs required to ensure such structural controllability, and characterize, and characterizes all (when not unique) possible configurations of the \emph{minimal} input matrix $B$. Furthermore, we show that the proposed solution methodology incurs \emph{polynomial complexity} in the number of state variables. By duality, the solution methodology may be readily extended to the structural design of the corresponding minimal output matrix (commonly denoted by $C$) that ensures structural observability.Comment: 8 pages, submitted for publicatio

On the Complexity of the Constrained Input Selection Problem for Structural Linear Systems

This paper studies the problem of, given the structure of a linear-time invariant system and a set of possible inputs, finding the smallest subset of input vectors that ensures system's structural controllability. We refer to this problem as the minimum constrained input selection (minCIS) problem, since the selection has to be performed on an initial given set of possible inputs. We prove that the minCIS problem is NP-hard, which addresses a recent open question of whether there exist polynomial algorithms (in the size of the system plant matrices) that solve the minCIS problem. To this end, we show that the associated decision problem, to be referred to as the CIS, of determining whether a subset (of a given collection of inputs) with a prescribed cardinality exists that ensures structural controllability, is NP-complete. Further, we explore in detail practically important subclasses of the minCIS obtained by introducing more specific assumptions either on the system dynamics or the input set instances for which systematic solution methods are provided by constructing explicit reductions to well known computational problems. The analytical findings are illustrated through examples in multi-agent leader-follower type control problems