2,300 research outputs found
Immigrant Entrepreneurs in the Massachusetts Biotechnology Industry (2007)
Immigrant entrepreneurs are co-founders in 25.7 percent of Massachusetts Biotechnology firms. In 2006, these immigrant-founded biotechnology companies produced over $7.6 billion dollars in sales and employed over 4,000 workers. The foreign-born founders came from across the globe but in larger numbers from Europe, Canada or Asia. Their firms specialize in the most complex, risky, life science-intensive aspects of biotechnology to seek knowledge directly applicable to human health. Biotechnology is a crucial industry for Massachhusetts and the evidence strongly suggests that immigrants have been key contributors to this industry by establishing new businesses as well as bringing intellectual capital and thereby contributing significantly to the overall economic growth of the Commonwealth
Bounding Bloat in Genetic Programming
While many optimization problems work with a fixed number of decision
variables and thus a fixed-length representation of possible solutions, genetic
programming (GP) works on variable-length representations. A naturally
occurring problem is that of bloat (unnecessary growth of solutions) slowing
down optimization. Theoretical analyses could so far not bound bloat and
required explicit assumptions on the magnitude of bloat. In this paper we
analyze bloat in mutation-based genetic programming for the two test functions
ORDER and MAJORITY. We overcome previous assumptions on the magnitude of bloat
and give matching or close-to-matching upper and lower bounds for the expected
optimization time. In particular, we show that the (1+1) GP takes (i)
iterations with bloat control on ORDER as well as
MAJORITY; and (ii) and
(and for )
iterations without bloat control on MAJORITY.Comment: An extended abstract has been published at GECCO 201
Portable high speed data acquisition system for ultrasound tissue characterization
http://www.worldcat.org/oclc/2622648
Nutrient Management in Beef Feedlots and Forage Replacement with Byproduct and Crop Residues
Finishing cattle performance and mass balance was evaluated with Micro-Aid was fed in diets containing wet distillers grains plus solubles (WDGS) at 35% (DM basis). Micro-Aid is a feed ingredient derived from a Yucca extract which contains saponins, and was included in the treatment diet at 1 g/hd daily in the supplement. There was no difference in performance and carcass characteristics between treatments. In the winter experiment, cattle fed Micro-Aid had a greater amount of OM and DM removed from the pen surface. Micro-Aid in the diet increased the amount of manure N and decreased N lossis in the winter. The addition of Micro-Aid in the diet resulted in no difference in nutrient mass balance during the summer. There was no difference in N excreted in manure or lost via volatilization in the summer experiment.
Supplementing cattle grazing smooth bromegrass pasture with crop residue and byproducts may be a viable option to extend the grazing season or increase carrying capacity. Two experiments (2010 and 2011) were conducted to determine the effect on forage intake of supplementing cattle grazing smooth bromegrass pasture with a byproduct and crop residue blend. Cattle grazed at 1) the recommending strocking rate (7.56 AUM/ha in 2010 or 9.46 AUM/ha in 2011) with no supplementation (CON) or 2) double the recommended stocking rate (15.1 AUM/ha in 2010 and 18.9 AUM/ha in 2011) with supplementation (SUP). In experiment 1 (2010) nonpregrnant, nonlactating cows grazed smooth bromegrass pasture from mid April to mid Spetmeber. Supplemented cows were fed a 35% Synergy and 65% wheat straw mixture daily. The ensiled mixture (46.6% DM) was fed from late April to mid-August and a fresh mixture (30.7% DM; mixed at feeding time) from mid-August to mid-September. In experiment 2 (2011), cows with spring born calves at side grazed from early May to mid-September. A fresh supplement of 30% MDGS and 70% cornstalk blend was fed daily. No differences in performance or diet quality were observed. Consequently, supplement replaced 40% of grazed forage intake in 2010 and 36.3% of forage intake in 2011. Supplementing byproduct and crop residue mixtures can replace forage intake of cattle grazing smooth bromegrass pasture.
Advisors: Galen E. Erickson and Terry Klopfenstei
Measurement, optimisation and control of particle properties in pharmaceutical manufacturing processes
Previously held under moratorium from 2 June 2020 until 6 June 2022.The understanding and optimisation of particle properties connected to their structure and morphology is a common objective for particle engineering applications either to improve materialhandling in the manufacturing process or to influence Critical Quality Attributes (CQAs) linked
to product performance. This work aims to demonstrate experimental means to support a rational development approach for pharmaceutical particulate systems with a specific focus on
droplet drying platforms such as spray drying.
Micro-X-ray tomography (micro-XRT) is widely applied in areas such as geo- and biomedical
sciences to enable a three dimensional investigation of the specimens. Chapter 4 elaborates
on practical aspects of micro-XRT for a quantitative analysis of pharmaceutical solid products
with an emphasis on implemented image processing and analysis methodologies. Potential
applications of micro-XRT in the pharmaceutical manufacturing process can range from the
characterisation of single crystals to fully formulated oral dosage forms. Extracted quantitative
information can be utilised to directly inform product design and production for process development or optimisation. The non-destructive nature of the micro-XRT analysis can be further
employed to investigate structure-performance relationships which might provide valuable insights for modelling approaches.
Chapter 5 further demonstrates the applicability of micro-XRT for the analysis of ibuprofen capsules as a multi-particulate system each with a population of approximately 300 pellets. The
in-depth analysis of collected micro-XRT image data allowed the extraction of more than 200
features quantifying aspects of the pellets’ size, shape, porosity, surface and orientation. Employed feature selection and machine learning methods enabled the detection of broken pellets
within a classification model. The classification model has an accuracy of more than 99.55%
and a minimum precision of 86.20% validated with a test dataset of 886 pellets from three capsules.
The combination of single droplet drying (SDD) experiments with a subsequent micro-XRT
analysis was used for a quantitative investigation of the particle design space and is described
in Chapter 6. The implemented platform was applied to investigate the solidification of formulated metformin hydrochloride particles using D-mannitol and hydroxypropyl methylcellulose
within a selected, pragmatic particle design space. The results indicate a significant impact of
hydroxypropyl methylcellulose reducing liquid evaporation rates and particle drying kinetics.
The morphology and internal structure of the formulated particles after drying are dominated
by a crystalline core of D-mannitol partially suppressed with increasing hydroxypropyl methylcellulose additions. The characterisation of formulated metformin hydrochloride particles with
increasing polymer content demonstrated the importance of an early-stage quantitative assessment of formulation-related particle properties.
A reliable and rational spray drying development approach needs to assess parameters of the
compound system as well as of the process itself in order to define a well-controlled and robust
operational design space. Chapter 7 presents strategies for process implementation to produce
peptide-based formulations via spray drying demonstrated using s-glucagon as a model peptide.
The process implementation was supported by an initial characterisation of the lab-scale spray
dryer assessing a range of relevant independent process variables including drying temperature
and feed rate. The platform response was captured with available and in-house developed Process Analytical Technology. A B-290 Mini-Spray Dryer was used to verify the development
approach and to implement the pre-designed spray drying process. Information on the particle
formation mechanism observed in SDD experiments were utilised to interpret the characteristics of the spray dried material.The understanding and optimisation of particle properties connected to their structure and morphology is a common objective for particle engineering applications either to improve materialhandling in the manufacturing process or to influence Critical Quality Attributes (CQAs) linked
to product performance. This work aims to demonstrate experimental means to support a rational development approach for pharmaceutical particulate systems with a specific focus on
droplet drying platforms such as spray drying.
Micro-X-ray tomography (micro-XRT) is widely applied in areas such as geo- and biomedical
sciences to enable a three dimensional investigation of the specimens. Chapter 4 elaborates
on practical aspects of micro-XRT for a quantitative analysis of pharmaceutical solid products
with an emphasis on implemented image processing and analysis methodologies. Potential
applications of micro-XRT in the pharmaceutical manufacturing process can range from the
characterisation of single crystals to fully formulated oral dosage forms. Extracted quantitative
information can be utilised to directly inform product design and production for process development or optimisation. The non-destructive nature of the micro-XRT analysis can be further
employed to investigate structure-performance relationships which might provide valuable insights for modelling approaches.
Chapter 5 further demonstrates the applicability of micro-XRT for the analysis of ibuprofen capsules as a multi-particulate system each with a population of approximately 300 pellets. The
in-depth analysis of collected micro-XRT image data allowed the extraction of more than 200
features quantifying aspects of the pellets’ size, shape, porosity, surface and orientation. Employed feature selection and machine learning methods enabled the detection of broken pellets
within a classification model. The classification model has an accuracy of more than 99.55%
and a minimum precision of 86.20% validated with a test dataset of 886 pellets from three capsules.
The combination of single droplet drying (SDD) experiments with a subsequent micro-XRT
analysis was used for a quantitative investigation of the particle design space and is described
in Chapter 6. The implemented platform was applied to investigate the solidification of formulated metformin hydrochloride particles using D-mannitol and hydroxypropyl methylcellulose
within a selected, pragmatic particle design space. The results indicate a significant impact of
hydroxypropyl methylcellulose reducing liquid evaporation rates and particle drying kinetics.
The morphology and internal structure of the formulated particles after drying are dominated
by a crystalline core of D-mannitol partially suppressed with increasing hydroxypropyl methylcellulose additions. The characterisation of formulated metformin hydrochloride particles with
increasing polymer content demonstrated the importance of an early-stage quantitative assessment of formulation-related particle properties.
A reliable and rational spray drying development approach needs to assess parameters of the
compound system as well as of the process itself in order to define a well-controlled and robust
operational design space. Chapter 7 presents strategies for process implementation to produce
peptide-based formulations via spray drying demonstrated using s-glucagon as a model peptide.
The process implementation was supported by an initial characterisation of the lab-scale spray
dryer assessing a range of relevant independent process variables including drying temperature
and feed rate. The platform response was captured with available and in-house developed Process Analytical Technology. A B-290 Mini-Spray Dryer was used to verify the development
approach and to implement the pre-designed spray drying process. Information on the particle
formation mechanism observed in SDD experiments were utilised to interpret the characteristics of the spray dried material
A new code for Fourier-Legendre analysis of large datasets: first results and a comparison with ring-diagram analysis
Fourier-Legendre decomposition (FLD) of solar Doppler imaging data is a
promising method to estimate the sub-surface solar meridional flow. FLD is
sensible to low-degree oscillation modes and thus has the potential to probe
the deep meridional flow. We present a newly developed code to be used for
large scale FLD analysis of helioseismic data as provided by the Global
Oscillation Network Group (GONG), the Michelson Doppler Imager (MDI)
instrument, and the upcoming Helioseismic and Magnetic Imager (HMI) instrument.
First results obtained with the new code are qualitatively comparable to those
obtained from ring-diagram analyis of the same time series.Comment: 4 pages, 2 figures, 4th HELAS International Conference "Seismological
Challenges for Stellar Structure", 1-5 February 2010, Arrecife, Lanzarote
(Canary Islands
Searching for Radio Pulsars in 3EG Sources at Urumqi Observatory
Since mid-2005, a pulsar searching system has been operating at 18 cm on the
25-m radio telescope of Urumqi Observatory. Test observations on known pulsars
show that the system can perform the intended task. The prospect of using this
system to observe 3EG sources and other target searching tasks is discussed.Comment: a training project about MSc thesi
«da kniff mich eine Idee». Anmerkungen zur getauschten Haut in Irmgard Keuns Das kunstseidene Mädchen (1932)
Um des Auswegs aus der Misere der kleinen Angestellten willen etwas erscheinen müssen, nicht etwas exemplarisch verkörpern, Mode- oder Fremdbildern unterworfen sein, nicht für sich selbst stehen, darunter leiden und scheitern _ Doris, die Heldin aus Irmgard Keuns Roman Das kunstseidene Mädchen, wird von einer Idee gekniffen, inszeniert ihre eigene Person zwischen den Selbst- und Fremdbildern des glamourösen Girls, als sie beschließt ihr Leben in einem Filmskript festzuhalten. Sie will schreiben wie Film, denn so will ihr das eigene Leben erscheinen und wird umso weniger so sein: Wie das Filmskript den Misserfolg ihrer Flucht chronometriert, so bezeichnet ein enteigneter Pelzmantel als Dingsymbol zugleich den Glanz eines Fremdbildes und einer Falle im Abseits der Weimarer Republik.Fretting and failing because she wants an image that will enable her to escape from a drab office-girl's existence, because she is not what she would like to be, because she is a slave to fashion and other people's perceptions, because she is not her true self. Such is the plight of Doris: the protagonist of Irmgard Keun's novel, The Artificial Silk Girl, has had a bright idea: she will cast herself as a glamour girl, mid-way between her own self-perception and the way she is perceived by others. She decides to turn her life into a movie script. She will write it as if her life were a film, because that is how she sees it, although in fact her life turns out to be anything but that. Just as the script gives a blow by blow account of her failure to escape, a stolen fur coat comes to embody, like a Dingsymbol, the glamorous image of herself as perceived by others, and is, in its turn, a trap which ensnares her on the margins of society in the Weimar Republic.Sufrimiento y fracaso por querer aparentar algo que le permita escapar de las penurias de las pequeñas oficinistas, por no ser lo que le gustaría, por estar supeditada a las modas o percepciones ajenas, por no ser ella misma. Esto es lo que le ocurre a Doris. A la protagonista de la novela de Irmgard Keun, La chica de seda artificial, se le ha antojado una idea: escenificarse como chica glamorosa, en un terreno que se encuentra entre su propia percepción y la ajena. Decide que va afijar su vida en un guión de cine. Quiere escribir como si su vida fuese una película, pero por más que quiera, sólo será un espejismo. De la misma manera que el guión cronometra el fracaso de su huida, un abrigo de piel expropiado encarna _como símbolo objeto_, el fulgor de una percepción ajena, y a su vez, una trampa que la remite a las márgenes de la sociedad de la República de Weimar.Um des Auswegs aus der Misere der kleinen Angestellten willen etwas erscheinen müssen, nicht etwas exemplarisch verkörpern, Mode- oder Fremdbildern unterworfen sein, nicht für sich selbst stehen, darunter leiden und scheitern _ Doris, die Heldin aus Irmgard Keuns Roman Das kunstseidene Mädchen, wird von einer Idee gekniffen, inszeniert ihre eigene Person zwischen den Selbst- und Fremdbildern des glamourösen Girls, als sie beschließt ihr Leben in einem Filmskript festzuhalten. Sie will schreiben wie Film, denn so will ihr das eigene Leben erscheinen und wird umso weniger so sein: Wie das Filmskript den Misserfolg ihrer Flucht chronometriert, so bezeichnet ein enteigneter Pelzmantel als Dingsymbol zugleich den Glanz eines Fremdbildes und einer Falle im Abseits der Weimarer Republik
Absolute velocity measurements in sunspot umbrae
In sunspot umbrae, convection is largely suppressed by the strong magnetic
field. Previous measurements reported on negligible convective flows in umbral
cores. Based on this, numerous studies have taken the umbra as zero reference
to calculate Doppler velocities of the ambient active region. To clarify the
amount of convective motion in the darkest part of umbrae, we directly measured
Doppler velocities with an unprecedented accuracy and precision. We performed
spectroscopic observations of sunspot umbrae with the Laser Absolute Reference
Spectrograph (LARS) at the German Vacuum Tower Telescope. A laser frequency
comb enabled the calibration of the high-resolution spectrograph and absolute
wavelength positions. A thorough spectral calibration, including the
measurement of the reference wavelength, yielded Doppler shifts of the spectral
line Ti i 5713.9 {\AA} with an uncertainty of around 5 m s-1. The measured
Doppler shifts are a composition of umbral convection and magneto-acoustic
waves. For the analysis of convective shifts, we temporally average each
sequence to reduce the superimposed wave signal. Compared to convective
blueshifts of up to -350 m s-1 in the quiet Sun, sunspot umbrae yield a
strongly reduced convective blueshifts around -30 m s-1. {W}e find that the
velocity in a sunspot umbra correlates significantly with the magnetic field
strength, but also with the umbral temperature defining the depth of the
titanium line. The vertical upward motion decreases with increasing field
strength. Extrapolating the linear approximation to zero magnetic field
reproduces the measured quiet Sun blueshift. Simply taking the sunspot umbra as
a zero velocity reference for the calculation of photospheric Dopplergrams can
imply a systematic velocity error.Comment: 10 pages, 7 figures, 2 tables, Appendix with 5 figure
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