The Virginia cider industry has grown rapidly in the past decade, and demands research-based recommendations for cider fermentation. This study evaluated relationships between the unique chemistry of apples and production of hydrogen sulfide (H2S) in cider fermentations. Yeast assimilable nitrogen (YAN) concentration and composition and residual fungicides influence H2S production by yeast during fermentation, but these factors have to date only been studied in wine grape fermentations. This study surveyed 12 Virginia-grown apple cultivars and found that the majority were severely deficient in YAN. The effects of three fungicides on cider fermentation were investigated; elemental sulfur, fludioxonil and fenbuconazole. Fenbuconazole adversely impacted fermentation kinetics. Sulfur and fludioxonil marginally impacted fermentation kinetics. Sulfur increased H2S production, but fludioxonil and fenbuconazole did not affect H2S production. There was no difference in fermentation kinetics and H2S between nitrogen sources arginine (approximating grape), asparagine (approximating apple) and ammonium (YAN supplement). Supplementation with methionine resulted in increased fermentation rate and decreased H2S production. The detrimental effects of fenbuconazole and beneficial effects of methionine were diminished with increasing total YAN. Contrary to previous findings, the most H2S was formed at 153 mg/L YAN which is above the generally recommended minimum to prevent H2S formation. These results indicate that apple juice chemistry may influence yeast metabolism during cider fermentation, in ways that have not been previously studied in grape fermentation. Our findings indicate the need for and contribute to the development of targeted fermentation management practices for cidermaking. / Master of Science in Life Sciences

Honey bees, Apis mellifera Linn., provide vital economic and ecological services via pollination while concurrently facing multiple interconnected stressors impacting their health. Many crops like apples, peaches, and cherries that add diversity and nutrition to our diet are wholly or partially dependent upon the pollination services of insects. Orchard crops are self-incompatible and commonly regarded as crops reliant on the pollination services of insects, and while previous studies have focused on the impact of bees to orchard crops during bloom, fewer studies have examined the reciprocal relationship of the orchards on honey bees, particularly across the entire foraging season. Here we investigated the foraging dynamics of honey bees in an orchard crop environment in Northern Virginia, United States. We decoded, mapped, and analyzed 3,710 waggle dances, which communicate the location of a valuable resource in the environment, for two full foraging seasons (April-October, 2018-2019), and, concurrent to the dance filming, collected pollen from returning foragers. We found that bees forage locally the majority of the time (< 2 km) throughout the season, with some long-range distances occurring in May after bloom (both 2018 and 2019) and in fall (2019). The shortest communicated median distances (0.50 km and 0.53 km), indicating abundant food availability, occurred during September in both years, paralleling the bloom of an important late season resource, goldenrod (Solidago). We determined, through plotting and analyzing the communicated forage locations and from the collected pollen from returning foragers, that honey bees forage more within apple orchards after the bloom (29.4% and 28.5% foraging) compared to during bloom (18.6% and 21.4% foraging) on the understory of clover and plantain. This post bloom foraging also exposes honey bees to the highest concentration of pesticides across the entire foraging season (2322.89 ppb pesticides versus 181.8 during bloom, 569.84 in late summer, and 246.24 in fall). Therefore, post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure, which may have important implications for management decisions of bees in orchards. / Master of Science in Life Sciences / Honey bee hives have been declining significantly in the United States, driven by a multitude of issues and stressors including pesticide exposure, disease, pests such as varroa mites, and poor nutrition caused by natural land being converted into development or agriculture. Agricultural landscapes, in particular, are often monocultures are saturated with pesticides creating a potentially hazardous environment, yet reliant on bees to provide pollination for crops. Because of this interconnected relationship between bees and flowers and the effects of stressors agricultural systems cause have with pollinators, it is necessary to understand how honey bees forage in these environments and what potential health risks they face. We investigated honey bees foraging dynamics in an apple orchard in Northern Virginia, United States by observing honey bee waggle dance behavior, where bees literally waggle back and forth for a certain time and at a certain angle telling their nestmates where a resource is, and collecting pollen from returning forager bees to better understand when, where, and upon what honey bees forage throughout the foraging season, which is when flowers are available and the weather warm enough (April – October). We found that bees mostly forage locally near the hive throughout the season, indicating that sufficient amount of food was available even after short bloom time of the apple (April to mid-May). We determined, through plotting and analyzing the waggle dance locations, that honey bees forage more within apple orchards after the bloom on mostly clover and plantain. This abundance of post bloom foraging also exposes honey bees to the highest amounts of pesticides across the entire foraging season. Post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure to honey bees.

Hazard Analysis Critical Control Point (HACCP) regulations for juice manufacture require the application of a process that will result in a 5-log reduction (99.999%) of the pertinent pathogen in the juice being processed. The use of ultraviolet (UV) light, as an alternative to traditional thermal processing, has been adopted by some juice processors as a means of meeting the HACCP 5-log performance standard. However, little research had been performed to determine the effect of UV when used in combination with antimicrobial agents that are commonly added to juice products. Therefore, the objectives of this work were (1) to determine if chemical preservatives and ultraviolet light have a combined effect on the reduction of Escherichia coli in apple cider, and (2) to determine the influence of adding chemical preservatives at different points in the processing of juice (i.e., either prior to or after ultraviolet light processing) on the reduction of Escherichia coli in apple cider. In this study, refrigerated (4°C) pasteurized apple cider that contained no added preservatives was inoculated with E. coli ATCC 25922, a surrogate strain for E. coli O157:H7, and exposed to UV (peak output: 254 nm). The following chemical preservatives were added to apple cider either prior to or after UV exposure: dimethyl dicarbonate (75 and 150 ppm), hydrogen peroxide (75 and 150 ppm), potassium sorbate (1000 and 2000 ppm), and sodium benzoate (1000 and 2000 ppm). Following UV exposure and chemical preservative application, inoculated juices were stored at 4°C for 72 hours. Samples were collected prior to and immediately after UV exposure and at 24, 48, and 72 hours of storage. At each sampling point, juice portions (0.1 ml) were serially diluted in peptone diluent (0.1%) and surface plated onto Tryptic Soy Agar (TSA). Counts of the bacterial colonies were made 48 hours after incubating plates at 35°C. Overall, reductions of E. coli were greater in cider treated with preservatives after UV processing than when preservatives were added prior to UV processing (P < 0.05). Furthermore, dimethyl dicarbonate and hydrogen peroxide were more effective than potassium sorbate and sodium benzoate in reducing E. coli populations in conjunction with UV (P < 0.05). When added prior to UV exposure, potassium sorbate was the least effective, allowing for the greatest survival (P < 0.05). This study describes the use of UV in conjunction with hydrogen peroxide and dimethyl dicarbonate as an effective method for producing a 5-log or greater reduction of E. coli O157:H7 in apple cider. / Master of Science

Our present knowledge, as indicated by the above data, proves that fire blight is due to a specific organism, a bacterium known in science as Bacillus amylovorus, which manifests itself in the following ways: 1. Blossom blight, due to the bacterial infecting the nectary of the flower and multiplying therein, later passing down into the stem by way of the ovary and pedicel. Apparent by the browning of the flowers, which later become blackened. 2. Twig blight, due to inoculation infections through wounds made by insects or other agencies on the young and tender shoots, blighting from the tips downward, the leaves turning brown and appearing as though scorched by fire. 3. Fruit blight, due to the progress of the bacteria up the pedicel into the pulp of the fruit; appearing as brownish or much darkened areas, later involving the entire fruit. 4. Canker blight, due to the entering of the larger branches by bacteria, conveyed by insect, bird, or mechanical agents, or by the bacillus working back from infected twigs, fruit-spurs, or water-sprouts. These cankers vary in size from barely visible areas to a girdling of the entire limb; they appear roughened and depressed with a distinct line separating the canker from the apparently healthy tissue. They are called "hold-over cankers." 5. Collar blight is nothing more than canker blight which attacks the base of the trunk usually through an infected water-sprout, borers, or mechanical injury. Trees afflicted with collar blight soon take on the sickly appearance of half starved trees, prematurely defoliating (partially or wholly), and finally dying. 6. Leaf blight, due largely to insect injury, the majority of infections the margin, either lateral or terminal, although central lesions are found. The blighted portion of the leaf being a light or yellowish brown with a faint purplish border at the advancing edge, which when active shows a narrow watery zone. During the warm sunny days soon after rains, when the trees are in blossom and the pollen gathering insects are busy visiting the flowers, and the hold-over cankers are exuding drops of the blight bacterial, fire blight begins its havoc. Insects come in contact with this gummy substance and later visit the blossoms, thereby inoculating the flowers with the active organism, blossom blight resulting. Bees are awarded first place in spreading the blight to the flowers but flies and all other insects which visit the bloom are also liable to spread the germ. Later on in the season, as long as the tree is in a vigorous stage of growth, the aphids, ants, leaf hoppers, borers, beetles, and in fact any of the biting or sucking insects which inhabit the apple tree, may spread the organism to the succulent tissue, causing twig blight, fruit blight, leaf blight, or body blight. It is a fact that the insect, which in one section of the country is most troublesome in disseminating blight-bacillus, may not be so important an agent in another section. Different varieties of apple trees may also vary in different sections as to their powers of resistance or susceptibility; the York Imperial being listed as a susceptible variety in Pennsylvania and Virginia while in West Virginia it seems to be quite resistant. We cannot control weather conditions which play so important a part in the spread of blight. The weather may put a tree in a responsive or susceptible condition to inoculation and may also control insect life to a great extent. And it is indeed difficult to try to "harden up" a tree by the application of phosphate and potash fertilizers and by the discontinuing of cultivation, especially when the soil is strong and rains are frequent. Hence the more practical methods must be followed: 1. Fight the insects which spread the disease. Spray with nicotine sulphate or some other tobacco extracts in combination with the early scab or codling moth sprays. Where "Black leaf 40" is used, the recommended strength is 1 to 800 parts of water. 2. Cut out the source of infection,- the hold over cankers--cutting back an inch or two into healthy bark, and disinfect the wound with bichloride of mercury (1-1000). Prune out all blighted branches and if possible cut out all blighted twigs, cutting back several inches into the healthy wood. A severe winter often kills the germs in the twigs. All the waste material should be hauled out of the orchard and burned. 3. It is well to discontinue cultivation and application of manure or nitrogenous fertilizers as soon as blight its appearance. 4. The trees are most susceptible to the attack when planted in low wet ground; hence drain the low spots in the orchard. Many bulletins have stated that winter pruning is inducive to wood and thus favors fire blight. Little attention should be paid to such recommendations for we need trees with good growth which will carry a crop of fruit and allow the sun to penetrate throughout the tree and color up the apples. Many fruit growers have bearing orchards and are not anticipating new ones, so to such,the talk of susceptible and resistant varieties means little. Then too, some of the susceptible varieties are the best commercial apples to raise, and when such is the case it means careful inspection for the hold-over cankers. It is however well to pay some attention to this fact when planting an orchard. What is needed badly is community spirit or cooperation in this difficult work of controlling fire blight. For if one's neighbor does not keep the disease out of his orchard, it is sure to spread to the adjoining orchard. So everyone should "pull together" and control blight which has and is now causing the apple grower heavy losses. / Master of Science

Master of Science

Form, space, rhythm, order, symmetry, balance, repetition, proportion and scale are few from a long checklist of principles that, if followed carefully by the designer, will result in "beautiful" architecture, or so I was told. However, what exactly is "beautiful"? In his book "The beautiful necessity" (1910, p.34) Claude Fayette Bragdon suggests that "Beauty is the name we give to truth we cannot understand". This statement implies that there is a hidden quality within each building, or even within each space, a quality that we can sense but cannot make sense of, a quality very similar to having a soul. The soul seems to linger on the threshold that divides two opposite worlds, it is always in-between. Between the dream and the awake, between the physical and the imaginary, between the conscious and the subconscious and between the real and the unreal. In this thesis, the "real" world consists of an animation studio (the program), the studio's staff and visitors, the selected site located in Alexandria, and it is bound by the building methods, materials and codes. The "unreal" world consists of four fictional characters that, assumingly, emerged from my subconscious and who live in a fictional dimension that overlaps ours.   The different encounters within the "real" world and within the "unreal" world, and also the interactions between the "real" and the "unreal" worlds are translated into an architectural language as an attempt to investigate the soul. / Master of Architecture

Gravimetric analysis was used to determine the release rates and longevities of several designs of pheromone dispensers for mating disruption of leafrollers and codling moth, Cydia pomonella (Linneaus). Release rates were described by linear equations for at least four months, but by the end of the season release rates tended to become erratic. Biocontrol’s red-brown codling moth dispenser lasted for up to four months, and one application of the dispenser in early May should control codling moth for the entire season in Virginia apple orchards. Ecogen and Hercon leafroller dispensers lasted for a shorter time than the codling moth dispensers and would require two applications per season to provide the best control of their target pests. In a commercial northern Virginia apple orchard, the effects of pheromone trap height and pheromone dispenser height on captures of the tufted apple bud moth, Platynota idaeusalis (Walker), were studied. Low traps (2.0 m) were more sensitive than high traps (4.5 m) for monitoring tufted apple bud moth. The number of moths caught in 1994 and 1995 in a two-hectare mating disruption plot with pheromone dispensers placed in the upper third of the tree was not significantly different from the number caught in a plot with pheromone dispensers placed at head height. Fruit damage was very high in both pheromone plots in 1994, but by 1995 it appeared that mating disruption was able to reduce fruit damage due to leafroller larvae. / Master of Science

Yes / This exploratory research aims to investigate social media users’ expectations of information systems (IS) products that are conceived but not yet launched. It specifically analyses social media data from Twitter about forthcoming smartphones and smartwatches from Apple and Samsung, two firms known for their innovative gadgets. Tweets related to the following four forthcoming IS products were retrieved from 1st January 2020 to 30th September 2020: (1) Apple iPhone 12 (6,125 tweets), (2) Apple Watch 6 (553 tweets), (3) Samsung Galaxy Z Flip 2 (923 tweets), and (4) Samsung Galaxy Watch Active 3 (207 tweets). These 7,808 tweets were analysed using a combination of the Natural Language Processing Toolkit (NLTK) and sentiment analysis (SentiWordNet). The online community was quite vocal about topics such as design, camera and hardware specifications. For all the forthcoming gadgets, the proportion of positive tweets exceeded that of negative tweets. The most prevalent sentiment expressed in Apple-related tweets was neutral but in Samsung-related tweets was positive. Additionally, it was found that the proportion of tweets echoing negative sentiment was lower for Apple compared with Samsung. This paper is the earliest empirical work to examine the degree to which social media chatter can be used by project managers for IS development projects, specifically for the purpose of end-users’ expectation management.

Smartwatches übernehmen im Alltag verschiedene Aufgaben wie das Annehmen von Telefongesprächen, das Empfangen von Nachrichten oder gar das Überwachen von Vitalfunktionen. Mittels eingebauter Sensoren lassen sich Puls- und Herzfrequenz kontrollieren, Blutdruck sowie Sauerstoffgehalt des Blutes messen und seit 2018 ein Elektrokardiogramm (EKG) aufzeichnen. Zudem verfügen Smartwatches über Warnsignale, die aktiviert werden, sobald ausgewählte Parameter einen gesundheitsgefährdenden Wert erreichen. Mit dem stetigen Tragen einer Smartwatch werden kontinuierlich Daten generiert, selbst wenn sich der Anwender im Schlaf befindet. Insbesondere für Patienten mit bereits bestehendem Krankheitsbild können diese Funktionen der Smartwatches ein nützliches Werkzeug in der Patientenbegleitung darstellen. Zu einer solchen Gruppe gehören Erwachsene mit angeborenen Herzfehlern (EMAH). Diese in Deutschland nachweislich am schlechtesten kardiologisch versorgte Patientengruppe weist sehr heterogene Krankheitsbilder auf. Geprägt durch die Diversität von Herzanatomien und die dadurch kardiophysiologisch veränderte Erregungsausbreitung können die Herzachsen, der Situs (Levo-, Meso- und Dextrokardie) und die ventrikuläre Anatomie (biventrikulär, single left und single right ventricle) von der Anatomie eines gesunden Herzens deutlich abweichen. Demzufolge kann die Funktionalität des Herzens und des Herzkreislaufes negativ beeinflusst werden. Klinische Daten zeigen bei Patienten mit angeborenen Herzfehlern im Verhältnis zur Allgemeinbevölkerung eine signifikant erhöhte Morbidität und Mortalität. Begründet ist dies in einem steigenden Risiko für die Entwicklung einer Herzinsuffizienz, einer infektiösen Endokarditis, einer Arrhythmie und ihrer Folgekomplikationen. Insbesondere Arrhythmien und deren Symptome können intermittierend auftreten, sodass bei Routineuntersuchungen von EMAH-Patienten beispielsweise die Anzeichen für eine Herzrhythmusstörung fehlen. Hier könnte die Anwendung von Verfahren, die ein mehr oder weniger kontinuierliches Aufzeichnen des Herzrhythmus ermöglichen, von großem Nutzen sein. Einen Ansatz hierzu bieten Smartwatches wie die Apple Watch Series 4, deren Verwendung zur Generierung von EKG-Ableitungen und zur Detektion von Herzrhythmusstörungen Gegenstand der vorliegenden Arbeit ist. Als erste Smartwatch erhielt die Apple Watch Series 4 im August 2018 eine De-novo-Zulassung der Food and Drug Administration (FDA). Diese ermöglicht das Aufzeichnen eines iEKGs (ein durch eine Smartwatch aufgezeichnetes EKG) mit einer einzelnen Ableitung, die der Einthoven-Ableitung I entspricht, sowie die Registrierung des Sinusrhythmus und unregelmäßigen Herzrhythmen. Mittels Positionsänderungen der Smartwatch und folglich Änderungen des Vektors konnten in Studien auch die Einthoven-Ableitungen II und III zuverlässig generiert werden. Die Studien von Samol et al. zeigten, dass bei herzgesunden Patienten die drei aufgezeichneten iEKG-Ableitungen eindeutig einem konventionell geschriebenen 12-Kanal-EKG zugeordnet werden konnten. Zudem wurden starke Korrelationen für die einzelnen EKG-Parameter aller drei iEKG-Ableitungen durch die Leipziger Gruppe um Shamloo et al. bei Herzgesunden nachgewiesen. Die vorliegende Arbeit ist die erste Studie, die sich qualitativ und quantitativ mit der Fragestellung auseinandersetzt, ob die mit einer Smartwatch generierten iEKGs der Ableitungen I, II und III nach Einthoven aussagekräftige Informationen für EMAH-Patienten liefern können. Hierfür wurden bei 106 erwachsenen Patienten mit angeborenen Herzfehlern (51 weiblich; 55 männlich) nach Genehmigung des Ethikantrages durch die Ethikkommission der Universität Leipzig und unterzeichneter Einverständniserklärung je ein 12-Kanal-EKG und drei iEKGs aufgezeichnet. Diese wurden daraufhin durch zwei unabhängige, auf dem Gebiet erfahrene Kardiologen in willkürlicher Reihenfolge verblindet ausgewertet. Die retrospektive Datenerhebung der Patientencharakteristika erfolgte im Anschluss. Analysiert und verglichen wurden hierfür die gängigen EKG-Parameter sowie der Rhythmustyp. Aus diesen Daten geht hervor, dass die drei iEKG-Ableitungen der EMAH-Patienten unabhängig von der individuellen Anatomie und den Patientencharakteristika zu vergleichbaren Ergebnissen in Bezug auf die Goldstandard-EKG-Ableitungen I, II und III nach Einthoven führten. In allen drei iEKG-Ableitungen zeigten sich starke bis sehr starke Korrelationen zwischen iEKG- und Goldstandard-EKG-Parametern. Signifikante, jedoch schwächere Korrelationen waren in den P- und T- Wellenintervallen zu verzeichnen. Grund hierfür könnte die bei der Aufzeichnung von iEKGs halbierte Schreibgeschwindigkeit (25mm/s) sein. Eine Schwäche zeigte insbesondere die iEKG-Ableitung III in ihrer Generierung. Während bei der iEKG-Ableitung I und II lediglich zwei Ableitungen nicht auswertbar waren, konnten bei der iEKG-Ableitung III zwölf Ableitungen in nicht auswertbarer Qualität geschrieben werden. Ebenso sind Defizite bei der Rhythmusanalyse ersichtlich. Insgesamt stimmten die Rhythmen der iEKGs mit den Rhythmen der konventionellen 12-Kanal-EKGs nur zu 77,4 Prozent überein. Dies liegt darin begründet, dass die Apple Watch einzig zwischen dem Sinusrhythmus und unregelmäßigen Herzrhythmen differenzieren kann. Von diesen abweichende pathologische Rhythmen (z.B. Pacemaker-Rhythmus) konnten nicht als solche detektiert werden und wurden dementsprechend fälschlicherweise vorwiegend dem Sinusrhythmus zugeordnet. Dass symptomatische und in das Aufzeichnen von iEKGs geschulte EMAH-Patienten selbstständig bei Arrhythmie-Symptomen ein EKG mittels der Apple Watch generieren können, ist als großer Fortschritt zu betrachten. Damit lassen sich diagnostische Hinweise während des Auftretens von Symptomen für das Vorliegen einer Herzrhythmusstörung unabhängig vom Arztbesuch allerorts detektieren und dokumentieren. Zwar vermag der durchschnittliche EMAH-Patient nicht zwischen relevanten und irrelevanten Herzrhythmusstörungen zu unterscheiden, dennoch kann der Patient bei vorliegender relevanter Pathologie ganz nach dem Motto “Time is Heart“ schnellstmöglich durch den behandelnden Arzt therapiert werden. Ob die nachweislich psychisch vorbelastete Patientengruppe durch die Anwendung der Smartwatch positiv oder negativ beeinflusst wird, kann mit der aktuellen Datenlage nicht bewertet werden und bedarf weiterer klinischer Untersuchungen. Die zunehmende Digitalisierung und Verfügbarkeit von Smartwatches, derer Weiterentwicklung sowie die stets wachsende Anzahl der EMAH-Patienten motivierten uns, diese neue Technologie mit Blick auf kardiologische Fragestellungen zu untersuchen. Diese Arbeit zeigt auf, dass zwischen den mit der Apple Watch Series 4 aufgezeichneten Einthoven-Ableitungen I, II und III und den korrespondierenden Ableitungen des konventionellen Goldstandard-12-Kanal-EKGs bei erwachsenen Patienten mit angeborenen Herzfehlern starke Korrelationen bestehen. Schlussfolgernd sind wir der Auffassung, dass die Apple Watch 4.1 im Sinne eines Eventrekorders bei erwachsenen Patienten mit angeborenen Herzfehlern unabhängig von den vorliegenden Patienteneigenschaften Anwendung finden kann, wobei sich die iEKG-Ableitungen I und II nach Einthoven als besonders zuverlässig erweisen. Es bleibt abzuwarten, welche Entwicklungen die nächsten Smartwatch-Generationen nehmen werden. Die fortschreitende Technologie mit Ausbau der Künstlichen Intelligenz (KI) ermöglicht es gegebenenfalls in der Zukunft, Patienten auf ihren Wunsch hin permanent kardiologisch zu überwachen. Bei vorliegender Pathologie könnten die Patienten frühzeitig gewarnt werden, um Folgekomplikationen effektiv vorzubeugen.

Yes / Reverse Osmosis (RO) membrane process has been commonly used for clarification and concentration of apple juice processes, due to significant advance in membrane technology, requirements for low energy and cost, and effective retention of aroma components. In this paper, a multi-stage RO industrial full-scale plant based on the MSCB 2521 RE99 spiral-wound membrane module has been used to simulate the process of concentrating apple juice and to identify an optimal multi-stage RO process for a specified apple juice product of high concentration measured in Brix. The optimisation problem is formulated as a Nonlinear Programming (NLP) problem with five different RO superstructures to maximise the apple juice concentration as well as the operating parameters such as feed pressure, flow rate and temperature are optimised. A simple lumped parameter model based on the solution-diffusion model and the contribution of all sugar species (sucrose, glucose, malic acid, fructose and sorbitol) to the osmotic pressure is assumed to represent the process. The study revealed that the multi-stage series RO process can optimise the product concentration of apple juice better than other configurations. It has been concluded that the series configuration of twelve elements of 1.03 m2 area improves the product apple juice concentration by about 142% compared to one element. Furthermore, the feed pressure and flow rate were found to have a significant impact on the concentration of the apple juice.