136 research outputs found
Practicing & Changing Engineering Design:a practice perspective on challenges in engineering design education
EVALUATING THE LONG-TERM EFFECTS OF LOGGING RESIDUE REMOVALS IN GREAT LAKES ASPEN FORESTS
Commercial aspen (Populus spp.) forests of the Great Lakes region are primarily managed for timber products such as pulp fiber and panel board, but logging residues (topwood and non-merchantable bolewood) are potentially important for utilization in the bioenergy market. In some regions, pulp and paper mills already utilize residues as fuel in combustion for heat and electricity, and progressive energy policies will likely cause an increase in biomass feedstock demand. The effects of removing residues, which have a comparatively high concentration of macronutrients, is poorly understood when evaluating long-term site productivity, future timber yields, plant diversity, stand dynamics, and consequently, appropriate silviculture.
These practices were evaluated throughout the western Upper Peninsula of Michigan using forest inventory data from harvested stands over the last 45 years. Assessment provided a framework of ecosystem carbon patterns across stand rotation, and comparisons reflected moderate losses in residue-bound carbon pools when captured. However, residue loads exceeded those recommended by established residue retention guidelines even in stands where residues were recovered for bioenergy. Soil nutrient pools exhibited declines under residue removal treatments on coarse textured soils. Aboveground biomass and timber yields did not vary according to residue treatment, and development of the aspen cohort was similar across all soil types, regardless of nutrient levels, an unexpected result. Stand dynamics varied by soil productivity class in the late stages of stand rotation, and imply that encouragement of non-crop trees for ecological purposes does not affect yields of the aspen resource. Predictions based upon historical growth and yield models showed mixed levels of accuracy when compared to observations. Analyses of vegetation communities and multivariate ordination methods revealed temporal patterns in species richness and increased heterogeneity under residue removal treatments. A spatially explicit sampling design was utilized to examine advances in harvesting technology on variance in stand level regeneration, soil nutrients, and residue estimates. Operator and equipment induced patterns in harvesting activity were found to increase residue loads with a concomitant decline in stem density and height growth across a large portion of the regenerating stand.
Collectively, these findings suggest that residue removal results in a minor decline in aboveground C stocks, and coarse textured soils may be susceptible to reductions in forest soil nutrient pools. Further, variations in growing conditions at the forest floor due to high residue loads may adversely affect understory vegetation communities. Finally, harvesting equipment, cut-block layout, and residue distribution can influence stand regeneration patterns, and warrants consideration in harvest and silvicultural planning
Tyr(b10) Prevents Stabilization of Bound Oxygen in Soybean Leghemoglobin
Root nodules are complex structures that occur on roots of many agronomically important plants such as soybeans. Root nodules are a symbiosis between the plant and soil-borne bacteria. Once formed, and functional, root nodules can fix atmospheric nitrogen and provide the plant with a pollution-free source of nitrogen for seed production. A basic component of functional and efficient root nodules are the heme proteins called leghemoglobins. Leghemoglobins can bind to, and transport molecular oxygen and thereby maintain a low oxygen environment within the root nodule, permitting the microaerobic bacteria to convert atmospheric dinitrogen into ammonia, which is then assimilated by the plant for growth. Thus understanding the oxygen-binding characteristics of leghemoglobin are of major importance from both a basic and applied point of view. In this paper we have shown that specific amino acid residues are critical for allowing the orderly binding and transfer of oxygen from leghemoglobins. Although several hypotheses have been advanced to account for the biochemical properties of leghemoglobins, this work is the first that clearly demonstrates the molecular consequences of amino acids that surround the heme-pocket. Using engineered mutant proteins and spectroscopy, the role of Tyr (B10) has been investigated in detail for several vertebrate and plant hemoglobins
Hardware-in-the-loop testing of control of a precooled desiccant air-cooling system
Increasing the energy efficiency of cooling in buildings is an important component of the management of global energy consumption. A super-efficient cooling system based on the evaporation concept has been developed, and initial simulation results using the MATLAB/Simulink software tool have already been published by our team. In this paper, we present the results of hardware-in-the-loop (HIL) testing of the real-time controller for the cooler. HIL testing is an engineering process in which the actual controller hardware and software are implemented and interfaced with a real-time simulated model of the controlled system. Using HIL testing, many real-world problems can be fixed before testing on the actual prototype. The controller design is implemented on a small-footprint industrial PC with CODESYS RTE and application code, while control software is implemented using IEC 61131-3 programming languages. Similarly, a real-time thermodynamic and input–output variable-based model of the room, environment, and cooler and its mechanical components (sensors and actuators) are modeled using another industrial PC with the same software tools. HIL test results show very good agreement with the offline simulations
PDGFRA defines the mesenchymal stem cell Kaposi's sarcoma progenitors by enabling KSHV oncogenesis in an angiogenic environment
Kaposi’s sarcoma (KS) is an AIDS-defining cancer caused by the KS-associated herpesvirus (KSHV). Unanswered questions regarding KS are its cellular ontology and the conditions conducive to viral oncogenesis. We identify PDGFRA(+)/SCA-1(+) bone marrow-derived mesenchymal stem cells (Pα(+)S MSCs) as KS spindle-cell progenitors and found that pro-angiogenic environmental conditions typical of KS are critical for KSHV sarcomagenesis. This is because growth in KS-like conditions generates a de-repressed KSHV epigenome allowing oncogenic KSHV gene expression in infected Pα(+)S MSCs. Furthermore, these growth conditions allow KSHV-infected Pα(+)S MSCs to overcome KSHV-driven oncogene-induced senescence and cell cycle arrest via a PDGFRA-signaling mechanism; thus identifying PDGFRA not only as a phenotypic determinant for KS-progenitors but also as a critical enabler for viral oncogenesis.Fil: Naipauer, Julian. Miami University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados UnidosFil: Rosario, Santas. Miami University; Estados Unidos. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados UnidosFil: Gupta, Sachin. Miami University; Estados Unidos. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados UnidosFil: Premer, Courtney. Miami University; Estados UnidosFil: Méndez Solís, Omayra. Miami University; Estados Unidos. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados UnidosFil: Schlesinger, Mariana. Miami University; Estados Unidos. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ponzinibbio, Maria Virginia. Miami University; Estados Unidos. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jain, Vaibhav. University of Florida; Estados UnidosFil: Gay, Lauren. University of Florida; Estados UnidosFil: Renne, Rolf. University of Florida; Estados UnidosFil: Chan, Ho Lam. Miami University; Estados UnidosFil: Morey, Lluis. Miami University; Estados UnidosFil: Salyakina, Daria. Miami University; Estados Unidos. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados UnidosFil: Abba, Martín Carlos. Miami University; Estados Unidos. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Inmunológicas Básicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Williams, Sion. Miami University; Estados UnidosFil: Hare, Joshua M.. Miami University; Estados UnidosFil: Goldschmidt Clermont, Pascal. Miami University; Estados UnidosFil: Mesri, Enrique Alfredo. Sylvester Comprehensive Cancer Center and Miami Center for AIDS Research; Estados Unidos. Miami University; Estados Unido
PDGFRA defines the mesenchymal stem cell Kaposi's sarcoma progenitors by enabling KSHV oncogenesis in an angiogenic environment
Kaposi’s sarcoma (KS) is an AIDS-defining cancer caused by the KS-associated herpesvirus (KSHV). Unanswered questions regarding KS are its cellular ontology and the conditions conducive to viral oncogenesis. We identify PDGFRA(+)/SCA-1(+) bone marrow-derived mesenchymal stem cells (Pα(+)S MSCs) as KS spindle-cell progenitors and found that pro-angiogenic environmental conditions typical of KS are critical for KSHV sarcomagenesis. This is because growth in KS-like conditions generates a de-repressed KSHV epigenome allowing oncogenic KSHV gene expression in infected Pα(+)S MSCs. Furthermore, these growth conditions allow KSHV-infected Pα(+)S MSCs to overcome KSHV-driven oncogene-induced senescence and cell cycle arrest via a PDGFRA-signaling mechanism; thus identifying PDGFRA not only as a phenotypic determinant for KS-progenitors but also as a critical enabler for viral oncogenesis.Centro de Investigaciones Inmunológicas Básicas y Aplicada
Changes in levels of angiotensin II and its receptors in a model of inverted stress-induced cardiomyopathy
Poetry of Arsen Dedić: Analysis of Certain Key Characteristics
Ovaj završni rad tematizira pjesništvo Arsena Dedića (1938. – 2015.) u kontekstu hrvatske postmodernističke književnosti. U uvodnom su dijelu izloženi osnovni biografski podaci o autoru, kao i teme kojima se ovaj rad bavi. Drugo poglavlje upoznaje čitatelja s vremenom ranog postmodernizma, govori o društveno-političkoj situaciji u svijetu i Hrvatskoj, a zatim se objašnjavaju uvijeti koji su pogodovali pozitivnoj recepciji Dedićeve prve zbirke Brod u boci (1971.). Potom se ta pjesnička zbirka analizira, te se u njoj traže postmodernistički elementi i elementi stiliziranog autobiografizma. U nastavku rada problematizira se motiv žene u njegovoj
poeziji te na koje se sve načine on javlja. Idući dio rada posvećen je smještanju Dedića u okvir mediteranističke književnosti, a zatim slijedi osvrt na motiv grada Zagreba u njegovoj poeziji. Konačno, analizira se i interpetira zbirka pjesama Padova (2004.) te se istražuje na koji način i zašto ona odudara od ostatka njegova opusa. U zaključku rezimira se sve navedeno i potvrđuje
estetska vrijednost Dedićeva pjesništva te se opravdava njegovo smještanje u kontekst postmodernizma
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