bluuebunny/crossref_metadata_2025_split huggingface dataset:
Migration patterns of pronghorn in southwestern North Dakota
Authors: Kolar Jesse L. , Millspaugh Joshua J. , Stillings Bruce A. 
Published: March 2011

AbstractWildlife managers need empirical data about pronghorn (Antilocapra americana) movements in North Dakota to assess whether mid‐summer surveys represent occupancy of pronghorn in hunting units during the fall hunting season. Using data from 121 radiocollared pronghorn we evaluated patterns of pronghorn migrations in southwestern North Dakota from 2004 to 2007. Pronghorn exhibited 2 primary movement patterns between summer and winter ranges: migrations >15 km (45%) and movement <15 km (55%). Most migratory pronghorn moved northeast or east in the spring and southwest or west in the fall. Average distance moved for migratory pronghorn was 70.6 km (range = 17.4–253 km). Mean date of pronghorn migration in spring was 20 March (SD = 20 days) and in fall was 22 October (SD = 17 days). Nearly all migratory pronghorn (97%) returned to within 15 km of their previous summer range, whereas only 61% of pronghorn returned to within 15 km of their previous winter range. Most pronghorn moved across hunting and survey unit boundaries; however, only 7 fall migrations occurred between the aerial survey and the hunting season. During years of our study, the mid‐summer survey provided representative information about hunting unit occupancy of radiocollared pronghorn for the fall hunting season. © 2011 The Wildlife Society
Simulating northern bobwhite population responses to nest predation, nesting habitat, and weather in south Texas
Authors: Rader Michael J. , Brennan Leonard A. , Brazil Kyle A. , Hernández Fidel , Silvy Nova J. 
Published: March 2011

AbstractNest predation is thought to be one of the major factors limiting northern bobwhite (Colinus virginianus) populations. We examined the relative impact of altering nest‐predation rate, nesting habitat, and weather (i.e., temp and precipitation) on northern bobwhite population dynamics in a hypothetical 15,000‐ha subtropical‐rangeland ecosystem in south Texas using a simulation model. The systems model consisted of a 3‐stage (i.e., eggs, juv, and ad) bobwhite population with dynamics influenced by variables affecting production, recruitment, nest predation, and mortality. We based model parameters on data collected from a 3‐yr nest‐predator study employing infrared‐camera technology, from ongoing field research using a radio‐marked population of wild bobwhites, and from the literature. The baseline simulated bobwhite population dynamics corresponded closely to empirical data, with no difference between medians of simulated (n = 30 yr) and observed bobwhite age ratios over a 28‐yr period. Similarly, a time‐series comparison of simulated and observed age ratios showed most (89%) observed values fell within the 5th and 95th percentiles of the simulated data over the 28‐yr period. We created simulated population scenarios representing 1) baseline historical conditions, 2) predator control, 3) low precipitation, 4) low precipitation with predator control, 5) high temperature, 6) high temperature with predator control, 7) reduced nest‐clump availability, and 8) reduced nest‐clump availability with predator control that resulted in considerably different median bobwhite densities over 10 yr. For example, under simulated predator control, populations increased by about 55% from the baseline scenario, whereas under simulated reduced nest‐clump availability, populations decreased by about 75% from the baseline scenario. Comparisons of time‐series for each scenario showed that reduced nest‐clump availability, low precipitation, and high temperature reduced bobwhite densities to a larger degree compared to a natural nest predation rate. Reduced nest‐clump availability resulted in the most substantial decline of simulated bobwhite densities. Simulations suggested that management efforts should focus on maintaining adequate nest‐clump availability and then possibly consider nest predator control as a secondary priority. © 2010 The Wildlife Society
Stopover habitats of spring migrating surf scoters in southeast Alaska
Authors: Lok Erika K. , Esler Daniel , Takekawa John Y. , de la Cruz Susan W. , Sean Boyd W. , Nysewander David R. , Evenson Joseph R. , Ward David H. 
Published: March 2011

AbstractHabitat conditions and nutrient reserve levels during spring migration have been suggested as important factors affecting population declines in waterfowl, emphasizing the need to identify key sites used during spring and understand habitat features and resource availability at stopover sites. We used satellite telemetry to identify stopover sites used by surf scoters migrating through southeast Alaska during spring. We then contrasted habitat features of these sites to those of random sites to determine habitat attributes corresponding to use by migrating scoters. We identified 14 stopover sites based on use by satellite tagged surf scoters from several wintering sites. We identified Lynn Canal as a particularly important stopover site for surf scoters originating throughout the Pacific winter range; approximately half of tagged coastally migrating surf scoters used this site, many for extended periods. Stopover sites were farther from the mainland coast and closer to herring spawn sites than random sites, whereas physical shoreline habitat attributes were generally poor predictors of site use. The geography and resource availability within southeast Alaska provides unique and potentially critical stopover habitat for spring migrating surf scoters. Our work identifies specific sites and habitat resources that deserve conservation and management consideration. Aggregations of birds are vulnerable to human activity impacts such as contaminant spills and resource management decisions. This information is of value to agencies and organizations responsible for emergency response planning, herring fisheries management, and bird and ecosystem conservation. © 2010 The Wildlife Society
Hibernacula selection by Townsend's big‐Eared bat in southwestern Colorado
Authors: Hayes Mark A. , Schorr Robert A. , Navo Kirk W. 
Published: March 2011

AbstractIn western United States, both mine reclamations and renewed mining at previously abandoned mines have increased substantially in the last decade. This increased activity may adversely impact bats that use these mines for roosting. Townsend's big‐eared bat (Corynorhinus townsendii) is a species of conservation concern that may be impacted by ongoing mine reclamation and renewed mineral extraction. To help inform wildlife management decisions related to bat use of abandoned mine sites, we used logistic regression, Akaike's information criterion, and multi‐model inference to investigate hibernacula use by Townsend's big‐eared bats using 9 years of data from surveys inside abandoned mines in southwestern Colorado. Townsend's big‐eared bats were found in 38 of 133 mines surveyed (29%), and occupied mines averaged 2.6 individuals per mine. The model explaining the most variability in our data included number of openings and portal temperature at abandoned mines. In southwestern Colorado, we found that abandoned mine sites with more than one opening and portal temperatures near 0°C were more likely to contain hibernating Townsend's big‐eared bats. However, mines with only one opening and portal temperatures of ≥10°C were occasionally occupied by Townsend's big‐eared bat. Understanding mine use by Townsend's big‐eared bat can help guide decisions regarding allocation of resources and placement of bat‐compatible closures at mine sites scheduled for reclamation. When feasible we believe that surveys should be conducted inside all abandoned mines in a reclamation project at least once during winter prior to making closure and reclamation recommendations. © 2010 The Wildlife Society.
The effect of anthropogenic resources on the space‐use patterns of golden jackals
Authors: Rotem Guy , Berger Haim , King Roni , (Kutiel) Pua Bar , Saltz David 
Published: March 2011

AbstractWe studied the influence of agricultural villages on space‐use patterns of golden jackals (Canis aureus Linnaeus) in the Mediterranean region of Israel. Villages in our research area attract jackals due to poor sanitation conditions in and around villages. As resources in these villages are abundant and predictable, we expected that space‐use patterns of jackals near those villages, including home‐range characteristics and movement paths, would differ from those of jackals inhabiting more natural areas. Using radio‐locations from 16 individuals (8 near villages and 8 from more natural areas), we found that mean home‐range size of jackals close to villages was 6.6 ± 4.5 km2, smaller than mean home‐range size of jackals in more natural areas (21.2 ± 9.3 km2, P = 0.001). Similarly, core area size of jackals near villages was 1.2 ± 0.92 km2, compared to 3.5 ± 1.6 km2 for individuals inhabiting more natural areas (P = 0.004). The core area/home‐range ratio was greater for jackals near villages than for those occupying more natural areas (0.122 ± 0.045 vs. 0.095 ± 0.037, respectively, P = 0.004). Jackals moved little during the day, with day ranges smaller for jackals near villages than away from them (1.65 ± 0.67 vs. 7.5 ± 5.6 km2, respectively, P = 0.028). However, jackals near villages moved as much at night as did jackals in more natural areas, although movement was in a less directional manner. Changes in distribution and predictability of resources due to anthropogenic activity affect not only the home‐range size of jackals, but also how they utilize and move through space. © 2011 The Wildlife Society.
Pyrometer optimiert selektives Weichlöten mit dem Laser
Authors: Reinl Steffen , Hoppert Bernd 
Published: March 2011

AbstractSelektives Löten elektronischer Komponenten ist ein weit verbreitetes Verfahren in der Produktion elektronischer Baugruppen. Doch zunehmend miniaturisierte Bauteile und Baugruppen lassen konventionelle selektive Lötverfahren an ihre Grenzen stoßen. Für diesen Anwendungsbereich hat der Diodenlaser neue Möglichkeiten eröffnet, insbesondere dann, wenn eine eigene Prozesskontrolle das berührungslose Lötverfahren steuert und überwacht.
Kleiner Laser, große Wirkung
Authors: Frede Maik , Moalem Anas 
Published: March 2011

AbstractDas Laserschweißen von Kupfer reduzierte sich aufgrund der hohen Prozessunsicherheit bisher auf nicht automatisierte, manuelle Applikationen und Anwendungen. Mit Hilfe eines neu entwickelten Laser‐Vorpulsmoduls konnte nun in Verbindung mit einem etablierten IR‐Lasersystem eine 100‐prozentige Prozesssicherheit beim Kupferschweißen demonstriert werden. Die zusätzlich eingebrachte Energie des Vorpulses ist dabei um einen Faktor 1000 kleiner als die Energie des eigentlichen Schweißpulses, ermöglicht jedoch definierte Prozessbedingungen. Das neue Verfahren führt weiterhin zu einer signifikanten Verbesserung der Energieeffizienz und des Schweißbilds.
Laserschweißen von Mischverbindungen
Authors: Standfuß Jens , Rath Wolfram , Valentin Martin , Falldorf Heiko 
Published: March 2011

AbstractGetrieben von der allgemeinen Forderung, Bauteile möglichst effizient eigenschafts‐ und gewichtsoptimiert herzustellen, sind stoffschlüssig gefügte Mischverbindungen in vielen Anwendungsbereichen gefordert. Das Schweißen von Kombinationen aus verschiedenen Werkstoffen ermöglicht, die spezifischen Eigenschaften der Stoffe optimal zu nutzen. Dies gestaltet sich jedoch in vielen Fällen schwierig, da die Komponenten sich deutlich in ihren thermophysikalischen und stofflichen Eigenschaften unterscheiden.
Arraytechnologie statt einzelner Laserdiode
Authors: Beier Bernard 
Published: March 2011

AbstractNicht nur in der Druckbranche muss es schnell gehen. Ein kompakter Laserkopf mit einer Vielzahl an Laserstrahlen weckt deshalb branchenübergreifendes Interesse. Überall dort, wo es gilt Strukturen auf große Flächen in kurzer Zeit aufzubringen, kann er zum Einsatz kommen.
Mikrostrukturieren mit Zukunft
Authors: Holtkamp Jens , Hartmann Claudia , Gillner Arnold , Beckemper Stefan , Dohrn Andreas , Eifel Stephan 
Published: March 2011

AbstractZum mikrometerfeinen Strukturieren funktioneller Oberflächen eigenen sich Kurzpuls‐ und Ultrakurzpulslaser inzwischen ebenso gut wie die klassischen Fertigungstechnologien. Das belegt auch die Vielzahl der Anwendungen, bei denen Laser derzeit die Oberflächen strukturieren. Speziell zum wirtschaftlichen Strukturieren von größeren Flächen bedarf es aber weiterer Forschungsaktivitäten. Sie öffnen den (Ultra‐) Kurzpulslasern zusätzliches Einsatzpotenzial.
Vereinfachtes Sicherheitskonzept bei voller Flexibilität
Authors: Leibold Kai 
Published: March 2011

AbstractStillstand heißt Rückschritt. Aus diesem Grund sind die kontinuierliche Weiterentwicklung bestehender Anlagenkonzepte und innovative Neuentwicklungen von entscheidender Bedeutung. Mit dem Konzept ROBLAS („Roboter‐Laser‐Schneiden”︁) wurde eine Technologie entwickelt, die die Kernziele: „höchste Flexibilität eines Industrieroboters mit einem stark vereinfachten Sicherheitskonzept”︁ für die Laserbearbeitung verwirklicht.
First, lead yourself
Authors: Daft Richard L. 
Published: March 2011

Abstract“Leaders usually know the correct way to lead others, so why don't they do it?” Richard L. Daft asks. Too often, Daft says, leaders focus on getting the best out of other people, without the necessary preparation, because “the first job of leadership is often getting the best out of yourself.” Personal mastery is essential, yet difficult to achieve. Why do we find it so difficult to lead ourselves and what steps can we take to achieve this difficult task? Daft offers new and insightful answers to these questions.
A Simple Access to the (Log/Normal) Molecular Weight Distribution Parameters of Polymers Using PGSTE NMR
Authors: Gong Xiaoliang , Hansen Eddy W. , Chen Qun 
Published: March 2011

AbstractA log/normal MWD is characterized by two parameters, its mean molecular weight M0 and width σ. It is demonstrated how these parameters can be obtained by model fitting a stretched exponential function (SEF), as characterized by two parameters β and DS, to the PGSTE response curve. Based on simulations, two general empirical equations relating β and DS to M0 and σ are found. The model enables the MWD characteristics to be determined if the scaling law between diffusivity and molecular weight is known. The sensitivity and relative error of σ and M0 are discussed and the applicability of the model is illustrated by analyzing experimental NMR response curve of some PEO samples. The key advantages of this technique are its simplicity, numerical robustness, and reliability. magnified image
Fabrication of Sealed µ‐Channels Through a Fast and Reliable Photopolymerization Process
Authors: Suriano Raffaella , Levi Marinella , Emilitri Elisa , Momo Chiara , Turri Stefano 
Published: March 2011

AbstractSealed microchannels and simple microfluidic networks with good efficiency and controlled quality of the structures were developed from a photocurable and PCR‐compatible material based on a PEG–methacrylate oligomers mixture. The influence of UV exposure time and of conversion degree on microchannel geometry were studied to obtain structures with controlled depth, vertical sidewalls, and good reproducibility. The roughness inside channels was as low as 50–100 nm, less than that typical of alternative LOC prototyping techniques such as micromilling. Efficient channel sealing was also achieved without using a different sealing material. Surface smoothness and hydrophilicity (static contact angle below 60°) allow spontaneous water flow inside the channels by capillarity without need of surface treatments. magnified image
Experimental techniques in free radical polymerization kinetics
Authors: Stickler Manfred 
Published: March 2011

AbstractA detailed review is given on experimental techniques in free‐radical polymerization kinetics. Besides the wellknown and familiar methods for the determination of monomer conversion (rate of polymerization) and initiator decomposition (rate of initiation) some further possibilities of getting more detailed information about the reaction system are shortly discussed (e.g. detection of end‐groups in the polymer, determination of molecular weight distributions).Special emphasis is given to some newer techniques with their abilities of automatic acquisition and treatment of data with the help of microprocessors.Problems associated with calibration procedures as well as error sources are discussed. Techniques for both steady state and non‐stationary polymerization experiments are reported.
Reactivities of acrylic monomers and their radicals in radical polymerization
Authors: Otsu Takayuki 
Published: March 2011

AbstractThe reactivities of acrylic derivatives in radical polymerization were largely dependent on polar, resonance and steric effects of their substituents. Although the change in ester alkyl substituents resulted in only polar effects, the introduction of the substituent into α‐position increased both resonance and steric effects, and that into β‐position increased steric effect greatly. The steric effects of o− and N–alkyl substituents in phenyl methacrylates and methacrylamides, respectively, were also important, i.e. 2,6‐di‐t‐butylphenyl methacrylate and N,N‐dialkylmeth‐acrylamides did not homopolymerize, although the respective acrylates and acrylamides could easily polymerize. It was noted that the steric effect by three alkyl groups bonded at α‐and o− or N‐positions played an important role. However, fumaric esters, β‐alkoxycarbonyl–acrylic esters, having bulky ester substituents were found to be readily polymerized to give high‐molecular‐weight and less‐ or non‐flexible polymers. In these polymerizations, the bimolecular termination is hindered, i.e. the life‐time of the propagating radical becomes longer. The propagating radicals were easily detectable from the polymerization mixtures by direct ESR measurement. Some features of these radical polymerizations are also discussed.
Chemistry and kinetics of the chain transfer reaction
Authors: Farina Mario 
Published: March 2011

AbstractChain transfer may be defined as a process in which the growing chain loses its capacity for further growth and the transfer agent (initiator, monomer, polymer, solvent or an extraneous compound) becomes capable of starting a new chain. This reaction has been subjected to extensive studies both for its relevance in interpreting the polymerization mechanism and for its practical importance as a method for controlling the molecular mass. In this communication the chemistry of the process is first described, then the classical kinetic approach based on the Mayo equation. Finally a selected number of recent results is discussed: the production of oligomers, the role of chain transfer in copolymerization, formation of branched polymers, catalyzed transfer and use of polyfunctional transfer agents.
Synthesis of telechelics and telomers by radical polymerization
Authors: Heitz W. 
Published: March 2011

AbstractSummaryTelechelics are α, Q‐bifunctional oligomers or low molecular weight polymers. They find use to obtain block copolymers in polycondensation and polyaddition reactions. Telechelics can be synthesized in an initiator controlled polymerization or in a telomerization.In the initiator controlled preparation of telechelics by radical polymerization the efficiency of the initiator can be higher than 0.9 if the polymerization is effected in bulk or at high concentrations. The initiators suitable to introduce functional end groups are discussed. Only those monomers can be used which terminate by combination. This is not a limitation in telomerization. Transfer agents resulting in polymers with two functional end groups are discussed.
Initiation, propagation and termination in free radical copolymerization
Authors: Russo Saverio 
Published: March 2011

AbstractAt present, the full sequence of events in free‐radical copolymerization cannot be described by a simple kinetic scheme. Indeed, several attempts to derive the copolymerization rate in homogeneous media on the basis of the usual assumptions considered valid for the polymerization of a single monomer have completely failed in terms of general validity. An overview of the various models, from the classical one based on the chemical control of the bimolecular termination reaction to the more modern approaches which include diffusion control of the termination stage, is presented and critically examined. The complex kinetic behavior which has already been evidenced in previous chapters for the polymerization of many monomer systems is re‐examined in terms of its relevance in the kinetics of the copolymerizing pair. The effect of the reaction medium separately on initiation, propagation, and termination is analyzed and new perspectives for experimental as well as theoretical studies are examined.
Studies of the dispersion polymerisation of methyl methacrylate in nonaqueous media
Authors: Winnik M A , Lukas R. , Chen W. F. , Furlong P. 
Published: March 2011

AbstractThe dispersion polymerisation process has been known for many years but has received comparatively little attention relative to conventional emulsion polymerisation. The dispersion polymerisation technique can be considered as a modified precipitation polymerisation that is carried out in the presence of an amphipathic polymeric stabiliser. This polymeric surfactant imparts colloidal stability to the precipitate that is formed during the reaction, thus allowing further growth into well‐defined, sterically stabilised latex particles. In this paper we discuss the effect that experimental variables such as stabiliser concentration, solvency of the disperson medium, initiator concentration and temperature have on the size of the particles that are formed. This is followed by a review of the polymerisation kinetics. It is concluded that when the dispersion medium is a non‐solvent for the polymer being formed then the locus of polymerisation is largely within the growing paticle and the system follows bulk polymerisation kinetics. The particles that are formed are usually submicron in size. As the solvency of the dispersion medium for the growing polymer particles is increased, then polymerisation of polymer in solution also occurs. The polymeric radicals that are formed in solution are then captured by growing particles. Consequently the locus of the particle polymerisation process changes and there is a concomitant change in the kinetics of polymerisation. Particles of up to 15 μm diameter have been formed in such systems. The reasons for these large variations in particle size are discussed in terms of the coalescence of primary particles that takes place during the polymerisation reaction.