Preliminary Evaluation of AIS Spectra Along a Topographic/moisture Gradient in the Nebraska Sandhills

Six spectral plots, each summarizing single-pixel reflectance for 128 channels of Airborne Imaging Spectrometer (AIS) data, were examined. The six sample pixels were located along a topographic/moisture gradient from lake surface to dune top in the Nebraska Sandhills. AIS spectra for various moisture regimes/vegetative zones appear quite logical, with a general positive relationship between increasing elevation (i.e., decreasing access of plant roots to water) and increasing reflectance in the spectral regions diagnostic of leaf-water content (i.e., bands centered on 1.65 and 2.20 microns)

Lichen Tour of Iowa State

For my project, I have sought to bridge the disconnect between technology and the natural world though the creation of “The Iowa State Lichen Trail”, which is hosted on a mobile friendly website. The website will guide, students, staff, faulty and visitors across ISU’s campus, stopping at multiple locations. Since most of the visitors will have never learned about this organism before, I have included a “getting to know us” and “basic anatomy” page to help orient visitors. At each stop, there are multiple pictures guiding the user to locate and identify the key features of the lichen. Each stop lists the names, both scientific and common, pertinent information about its ecology, and at several spots, how to distinguish the species from similar species. I collected, identified, and chose all the lichens represented on the webpage. I intentionally chose long-living, permanent lichen to ensure the trail can be enjoyed for the years to come

Increased expression of the oxidative pentose phosphate pathway and gluconeogenesis in anaerobically growing xylose-utilizing Saccharomyces cerevisiae

<p>Abstract</p> <p>Background</p> <p>Fermentation of xylose to ethanol has been achieved in <it>S. cerevisiae </it>by genetic engineering. Xylose utilization is however slow compared to glucose, and during anaerobic conditions addition of glucose has been necessary for cellular growth. In the current study, the xylose-utilizing strain TMB 3415 was employed to investigate differences between anaerobic utilization of glucose and xylose. This strain carried a xylose reductase (<it>XYL1 </it>K270R) engineered for increased NADH utilization and was capable of sustained anaerobic growth on xylose as sole carbon source. Metabolic and transcriptional characterization could thus for the first time be performed without addition of a co-substrate or oxygen.</p> <p>Results</p> <p>Analysis of metabolic fluxes showed that although the specific ethanol productivity was an order of magnitude lower on xylose than on glucose, product yields were similar for the two substrates. In addition, transcription analysis identified clear regulatory differences between glucose and xylose. Respiro-fermentative metabolism on glucose during aerobic conditions caused repression of cellular respiration, while metabolism on xylose under the same conditions was fully respiratory. During anaerobic conditions, xylose repressed respiratory pathways, although notably more weakly than glucose. It was also observed that anaerobic xylose growth caused up-regulation of the oxidative pentose phosphate pathway and gluconeogenesis, which may be driven by an increased demand for NADPH during anaerobic xylose catabolism.</p> <p>Conclusion</p> <p>Co-factor imbalance in the initial twp steps of xylose utilization may reduce ethanol productivity by increasing the need for NADP+ reduction and consequently increase reverse flux in glycolysis.</p

Comparison of heterologous xylose transporters in recombinant Saccharomyces cerevisiae

Abstract Background Baker's yeast (Saccharomyces cerevisiae) has been engineered for xylose utilization to enable production of fuel ethanol from lignocellulose raw material. One unresolved challenge is that S. cerevisiae lacks a dedicated transport system for pentose sugars, which means that xylose is transported by non-specific Hxt transporters with comparatively low transport rate and affinity for xylose. Results In this study, we compared three heterologous xylose transporters that have recently been shown to improve xylose uptake under different experimental conditions. The transporters Gxf1, Sut1 and At5g59250 from Candida intermedia, Pichia stipitis and Arabidopsis thaliana, respectively, were expressed in isogenic strains of S. cerevisiae and the transport kinetics and utilization of xylose was evaluated. Expression of the Gxf1 and Sut1 transporters led to significantly increased affinity and transport rates of xylose. In batch cultivation at 4 g/L xylose concentration, improved transport kinetics led to a corresponding increase in xylose utilization, whereas no correlation could be demonstrated at xylose concentrations greater than 15 g/L. The relative contribution of native sugar transporters to the overall xylose transport capacity was also estimated during growth on glucose and xylose. Conclusions Kinetic characterization and aerobic batch cultivation of strains expressing the Gxf1, Sut1 and At5g59250 transporters showed a direct relationship between transport kinetics and xylose growth. The Gxf1 transporter had the highest transport capacity and the highest xylose growth rate, followed by the Sut1 transporter. The range in which transport controlled the growth rate was determined to between 0 and 15 g/L xylose. The role of catabolite repression in regulation of native transporters was also confirmed by the observation that xylose transport by native S. cerevisiae transporters increased significantly during cultivation in xylose and at low glucose concentration.</p

Några tvistefrågor rörande utsäde och avgifter i Roskildeboken

Artiklen er et indlæg i diskussionen om tolkning af forskellige afgifter og ejendomme i Roskildebispens jordebog fra 1370 og deres mulige forhold til hinanden

Hur har andrahandslägenheter i Malmö kommun fördelats till hemlösa över tid? : En studie av prioriteringar och exkluderingar

Under 1980-talet började flera svenska kommuner etablera en sekundär bostadsmarknad, där socialtjänsten hyrde ut lägenheter i andra hand till hemlösa klienter som var utestängda från den ordinarie bostadsmarknaden. Orsaken var en kombination av fastighetsägares ”höga trösklar”, socialtjänstens behov av boenden för hemlösa klienter och båda parters strävan efter kontroll. Möjligheten att tilldelas en lägenhet i andra hand var och är nämligen starkt villkorad från både bostadsföretagens och socialtjänstens sida. För hyresgästen präglas boendet också av osäkerhet: frånvaron av besittningsskydd, korta hyresperioder och tilläggsbestämmelser i hyresavtalet skiljer denna boendeform från vad som normalt gäller för hyresgäster, samtidigt som den utgör det högsta steget i en föreställd ”boendetrappa”.Rapporten är den första från forskningsprojektet Skånska hem vid Socialhögskolan,Lunds universitet, och undersöker hur de skånska kommunerna arbetar för att ordna bostäder till nyanlända respektive hemlösa. Författaren redogör för och analyserar Malmö kommuns uthyrning av andrahandslägenheter till hemlösa under en fyrtioårsperiod, från 1980-talets början och fram till halvårsskiftet 2021.Hur har socialtjänstens organisation förändrats över tid och vilka implikationer har det haft för detta bostadssegment? Vilka aktörer har deltagit i urvalet av hyresgäster till dessa bostäder och hur har de interagerat? Och hur har målgruppen för kommunens andrahandslägenheter kategoriserats över tid – vilka har prioriterats och vilka har exkluderats? Det är några av de frågor som väglett rapporten, och som besvaras genom en analys av ett stort antal intervjuer, dokument och observationer

A mutated xylose reductase increases bioethanol production more than a glucose/xylose facilitator in simultaneous fermentation and co-fermentation of wheat straw

Genetically engineered Saccharomyces cerevisiae strains are able to ferment xylose present in lignocellulosic biomass. However, better xylose fermenting strains are required to reach complete xylose uptake in simultaneous saccharification and co-fermentation (SSCF) of lignocellulosic hydrolyzates. In the current study, haploid Saccharomyces cerevisiae strains expressing a heterologous xylose pathway including either the native xylose reductase (XR) from P. stipitis, a mutated variant of XR (mXR) with altered co-factor preference, a glucose/xylose facilitator (Gxf1) from Candida intermedia or both mXR and Gxf1 were assessed in SSCF of acid-pretreated non-detoxified wheat straw. The xylose conversion in SSCF was doubled with the S. cerevisiae strain expressing mXR compared to the isogenic strain expressing the native XR, converting 76% and 38%, respectively. The xylitol yield was less than half using mXR in comparison with the native variant. As a result of this, the ethanol yield increased from 0.33 to 0.39 g g-1 when the native XR was replaced by mXR. In contrast, the expression of Gxf1 only slightly increased the xylose uptake, and did not increase the ethanol production. The results suggest that ethanolic xylose fermentation under SSCF conditions is controlled primarily by the XR activity and to a much lesser extent by xylose transport

Utvärdering av produktionsmetod platsgjutet stombyggande : tillämpning av värdeflödesanalys och activity sampling.

Syftet med rapporten är att kartlägga och analysera hur värdeflödet i samband med platsgjutning av en stomme fungerar idag, med avseende på bland annat arbetsfördelning, genomloppstider, resursanvändning, mellanlagring och informationsflöde. En utvärdering görs av hur metoderna Activity sampling och Värdeflödesanalys fungerar för kartläggning inom byggbranschen och hur resultaten från studier med dessa metoder kan nyttjas för att lokalisera förbättrande åtgärder. Activity Sampling är en metod för mätning av aktivitet, genom en serie momentana observationer av pågående arbete, vid slumpmässiga tidpunkter. Värdeflödesanalys är en teknik, med ursprung inom Toyota Production System, som används för att kartlägga produktionen och få en överskådlig bild av vad en produkt går igenom för skeden. Metoden används främst med avsikten att förbättra värdeflödet