Population models with partial migration

Populations exhibiting partial migration consist of two groups of individuals: Those that mi- grate between habitats, and those that remain fixed in a single habitat. We propose several discrete-time population models to investigate the coexistence of migrants and residents. The first class of models is linear, and we distinguish two scenarios. In the first, there is a single egg pool to which both populations contribute. A fraction of the eggs is destined to become migrants, and the remainder become residents. In a second model, there are two distinct egg pools to which the two types contribute, one corresponding to residents and another to migrants. The asymptotic growth or decline in these models can be phrased in terms of the value of the basic reproduction number being larger or less than one respectively. A second class of models incorporates density dependence effects. It is assumed that increased densities in the various life history stages adversely affect the success of transitioning of individuals to subsequent stages. Here too we consider models with one or two egg pools. Although these are nonlinear models, their asymptotic dynamics can still be classified in terms of the value of a locally defined basic reproduction number: If it is less than one, then the entire population goes extinct, whereas it settles at a unique fixed point consisting of a mixture of residents and migrants, when it is larger than one. Thus, the value of the basic reproduction number can be used to predict the stable coexistence or collapse of populations exhibiting partial migration

Vascular microarray profiling in two models of hypertension identifies caveolin-1, Rgs2 and Rgs5 as antihypertensive targets

BACKGROUND: Hypertension is a complex disease with many contributory genetic and environmental factors. We aimed to identify common targets for therapy by gene expression profiling of a resistance artery taken from animals representing two different models of hypertension. We studied gene expression and morphology of a saphenous artery branch in normotensive WKY rats, spontaneously hypertensive rats (SHR) and adrenocorticotropic hormone (ACTH)-induced hypertensive rats. RESULTS: Differential remodeling of arteries occurred in SHR and ACTH-treated rats, involving changes in both smooth muscle and endothelium. Increased expression of smooth muscle cell growth promoters and decreased expression of growth suppressors confirmed smooth muscle cell proliferation in SHR but not in ACTH. Differential gene expression between arteries from the two hypertensive models extended to the renin-angiotensin system, MAP kinase pathways, mitochondrial activity, lipid metabolism, extracellular matrix and calcium handling. In contrast, arteries from both hypertensive models exhibited significant increases in caveolin-1 expression and decreases in the regulators of G-protein signalling, Rgs2 and Rgs5. Increased protein expression of caveolin-1 and increased incidence of caveolae was found in both smooth muscle and endothelial cells of arteries from both hypertensive models. CONCLUSION: We conclude that the majority of differences in gene expression found in the saphenous artery taken from rats with two different forms of hypertension reflect distinctive morphological and physiological alterations. However, changes in common to caveolin-1 expression and G protein signalling, through attenuation of Rgs2 and Rgs5, may contribute to hypertension through augmentation of vasoconstrictor pathways and provide potential targets for common drug development

Marksmanship Mind Body Alignment

This report investigates the link between marksmanship, academic performance and fitness. The results of this project may establish justification to sustain and grow the Iowa State Naval Reserve Officer Training Corps (NROTC) marksmanship program. To investigate the link between marksmanship and fitness the student used a pulse oximeter to measure pulses and blood oxygen saturations of both new NROTC marksmen and non-marksmen. The student collected self-reported GPA’s before and after joining the marksmanship program, to study the link between marksmanship and academic performance. The student also issued a survey to assess the impact of marksmanship on concentration, stress levels, confidence, and attention to detail. Finally, the student examined the link between marksmanship performance, pulse, and oxygen saturation to determine whether marksmanship proficiency affected fitness. Marksmen had higher pulses than non-marksmen. However, marksmanship practice did not appreciably impact oxygen saturation. Marksmanship training did not significantly impact GPA’s. However, marksmen reported equal or better concentration, confidence, and attention to detail since starting marksmanship. Among more experienced marksmen, accuracy scores increased when heart rates decreased and oxygen saturation increased. There may be a correlation between marksmanship, fitness, and academics, but larger samples and experienced or competitive collegiate marksmen are required to clarify conclusions

Development and Characterization of a Filter-Based Bioaerosol Sampler Capable of Integration into Small Unmanned Aerial Systems

In developing functional SUAS, performance characteristics that indicate system capability should be developed prior to initiating initial system design. Key performance parameters should be developed involving all system elements (including vehicle body, operator, ground station, sensor, and algorithm or processing module). A bioaerosol sampler designed specifically for the use in SUAS was characterized based on designated performance measures to determine overall effectiveness compared to traditional bioaerosol samplers. For a system with a goal of accurately identifying and quantifying areas of airborne biological contamination or surveying background levels for longitudinal studies, performance parameters such as weight of the vehicle with payload and sampler specific parameters will be quantitatively evaluated. These sampler-specific parameters include operational noise levels, power demand compared to performance, and sampling fraction. These were evaluated in a series of lab-based tests to determine if the developed model of bioaerosol sampler could be deployed for use in military environments. Overall, it was found that the developed EOS inlet oversampled for the background concentrations compared to the modeled performance for the inlet, and oversampled compared to the closed face cassette filter. This may be due to ground effects acting on the system—as the bottom placement for the sampler performed worse than expected based on previous research in comparison to the sampler closer to the rotors

Changes in the Expression of miR-381 and miR-495 Are Inversely Associated with the Expression of the MDR1 Gene and Development of Multi-Drug Resistance

Multidrug resistance (MDR) frequently develops in cancer patients exposed to chemotherapeutic agents and is usually brought about by over-expression of P-glycoprotein (P-gp) which acts as a drug efflux pump to reduce the intracellular concentration of the drug(s). Thus, inhibiting P-gp expression might assist in overcoming MDR in cancer chemotherapy. MiRNAome profiling using next-generation sequencing identified differentially expressed microRNAs (miRs) between parental K562 cells and MDR K562 cells (K562/ADM) induced by adriamycin treatment. Two miRs, miR-381 and miR-495, that were strongly down-regulated in K562/ADM cells, are validated to target the 3'-UTR of the MDR1 gene. These miRs are located within a miR cluster located at chromosome region 14q32.31, and all miRs in this cluster appear to be down-regulated in K562/ADM cells. Functional analysis indicated that restoring expression of miR-381 or miR-495 in K562/ADM cells was correlated with reduced expression of the MDR1 gene and its protein product, P-gp, and increased drug uptake by the cells. Thus, we have demonstrated that changing the levels of certain miR species modulates the MDR phenotype in leukemia cells, and propose further exploration of the use of miR-based therapies to overcome MDR.The authors would like to declare that we received funding from a commercial source, i.e. Bioplatforms Australia. This does not alter the authors' adherence to all PLOS ONE policies on sharing data and materials

Operation and Utilisation of the High Flux Reactor: Annual Report 2014

The High Flux Reactor (HFR) at Petten is managed by the Institute for Energy and Transport (IET) of the European Commission's Joint Research Centre (JRC) and operated by the Nuclear Research and consultancy Group (NRG) which is also the licence holder and responsible for its commercial activities. The High Flux Reactor (HFR) operates at 45 MW and is of the tank-in-pool type, light water cooled and moderated. It is one of the most powerful multi-purpose materials testing reactors in the world and one of the world's leaders in target irradiation for the production of medical radioisotopes.JRC.F.4 - Innovative Technologies for Nuclear Reactor Safet

Operation and Utilisation of the High Flux Reactor: Annual Report 2013

The High Flux Reactor (HFR) at Petten is managed by the Institute for Energy and Transport (IET) of the European Commission's Joint Research Centre (JRC) and operated by the Nuclear Research and consultancy Group (NRG) which is also the licence holder and responsible for its commercial activities. The High Flux Reactor (HFR) operates at 45 MW and is of the tank-in-pool type, light water cooled and moderated. It is one of the most powerful multi-purpose materials testing reactors in the world and one of the world's leaders in target irradiation for the production of medical radioisotopes.JRC.F.4-Innovative Technologies for Nuclear Reactor Safet

Restoration of Aspen in Different Stages of Mortality in Southern Utah

Aspen clones of an aspen-dominated community in Southwestern Utah are declining, some having experienced high mortality coupled with in sufficient regeneration. The objectives of this study were to (I) determine if decadent, non-regenerating mature aspen stands could be regenerated through disturbance of the 111 auxin/cytokinin hormone relationship by clearcutting; (2) determine the extent of ungulate use of regenerating aspen ramets. Clearcuts were made in late summer of 2001 in 10 different clones that exhibited various levels of decline on a continuum from relatively healthy to extremely deteriorated. Nested wildlife/livestock exclosures were constructed in each clearcut plot, as well as in a corresponding uncut control plot. In the fall of 2002, regenerating suckers were counted. In addition, vigor and ungulate utilization of these suckers were measured in the wildlife and livestock exclosures, as well as in an unprotected portion of the clearcut and control plots. Regeneration of the clearcut plots ranged from none in the most decadent clones, to 75,000 stems/ha in the least decadent clone, and was significantly greater than the control plots. Vigor, as measured by height of the suckers, was 1.5 to 2.1 times greater in the clearcut plots than in the control plots. Seventy-three percent of the suckers in the unprotected portion of the plots were heavily browsed, while only 12% were not browsed. Successful regeneration of aspen clones is heavily dependent upon clone decadence. Unregulated browsing pressure may limit the clone’s ability to successfully restock and remain on the landscape