bluuebunny/crossref_metadata_2025_split huggingface dataset:
ULTRASTRUCTURE OF EARLY DEVELOPMENT IN THE FEMALE REPRODUCTIVE SYSTEM OF POLYSIPHONIA HARVEYI BAILEY (CERAMIALES, RHODOPHYTA)1
Authors: Broadwater Sharon T. , Scott Joe 
Published: August 2007

ABSTRACTPrefertilization and immediate postfertilization development in the female reproductive branch of Polysiphonia harveyi (Bailey) was studied with the electron microscope. Results pertaining to prefertilization morphology and development are consistent with those established in earlier light microscopic studies, but several unexpected ultrastructural characteristics were discovered. The mature carpogonium was found to have double membrane‐bound vacuoles of nuclear origin and the carpogonial nucleus contained a nucleolus with a distinctive crystalline lattice. Trichogynes lacked a nucleus. Of particular interest was the discovery of a highly structured channel of smooth endoplasmic reticulum (SER) which extended uninterrupted, except for pit connections, through the carpogonial branch. It is suggested that the message of fertilization is conducted through the SER channel from the carpogonium to the support cell. Few observations were made on postfertilization branches, but evidence of direct fusion between the carpogonium and auxiliary cell was fairly conclusive. Pit plugs in the female branch were found to be of three morphological types differing by the presence and number of pit membranes. We have designated these plugs Type I–III since differential functioning was not fully ascertained. Our data suggest that pit membranes may serve to stabilize the plug and that those plugs without membranes are more readily dismantled to allow cytoplasmic continuity between cells.
TRANSPORT OF AMINO ACIDS BY THE SOIL ALGA STICHOCOCCUS BACILLARIS1
Authors: Carthew Richard W. , Hellebust Johan A. 
Published: August 2007

ABSTRACTThe green alga Stichococcus bacillaris Naeg. is able to take up at least eleven amino acids. All of these except glutamic and aspartic acids are transported by carrier systems that obey saturation kinetics. The acidic amino acids enter the cell by passive diffusion. Michaelis‐Menten parameters (Ks and Vmax) were calculated for several amino acids. All obey simple Michaelis‐Menten behavior except for 2‐methylalanine and leucine which may have double carrier systems of different affinities. Interactions between pairs of amino acids suggest that there is at least one carrier system specific for basic amino acids and probably several systems specific for neutral amino acids. Further analysis of neutral amino acid interactions reveal that the uptake of several amino acids is incompletely inhibited by competitor uptake at infinite concentration. The simplest interpretation of the data is the operation of three carrier systems for neutral amino acids, one of which has higher affinity and broader specificity than the other two. The amino acid carrier systems appear to operate by an active mechanism. The metabolic poison DCCD inhibits uptake up to 99%. The capacities of the neutral amino acid carrier systems are increased when cells are grown in medium containing suboptimal concentrations of nitrogen.
DISTRIBUTION OF CARBON AMONG PHOTOSYNTHETIC END‐PRODUCTS IN PHYTOPLANKTON OF THE EASTERN CANADIAN ARCTIC1
Authors: William K. W. Li  , Platt Trevor 
Published: August 2007

ABSTRACTThe distribution of 14C among photosynthetic end‐products was examined in eastern Canadian arctic phytoplankton, with particular emphasis on the synthesis of lipids. The pattern of 14C distribution for phytoplankton at each of three depths was generally similar among populations from 12 stations. About 18% of the total 14C fixed was incorporated into lipids. At one station, phytoplankton were experimentally subjected to temperature and light conditions different from those in situ: lipid‐14C did not exceed 30% of total 14C fixed within the temperature range ‐1.0 to 6.0° C and irradiance range 1 to 700 W · m−2. It is suggested that low temperatures and low light intensities, even when, maintained for prolonged periods, are not fully sufficient conditions for eliciting high relative rates of 14C incorporation into lipids. It is possible that differences in species composition may be a factor accounting for different patterns of 14C distribution between north and south polar phytoplankton under apparently similar environmental conditions.
THE IDENTITY AND REPRODUCTIVE STRUCTURES OF A MISPLACED SOLENOPORA (RHODOPHYCOPHYTA) FROM THE ORDOVICIAN OF SOUTHWESTERN OHIO AND EASTERN INDIANA1
Authors: Blackwell Will H. , Marak Joe H. , Powell Martha J. 
Published: August 2007

ABSTRACTA study of certain fossil, limestone‐forming algae in upper Ordovician beds (Elkhorn and Whitewater Formations of the Richmond Subseries of the Cincinnati Series) in southwestern Ohio and adjacent eastern Indiana culminated with the conclusion that an organism originally described as a sponge, and later placed in the genus Girvanella Nicholson and Etheridge (Cyanochloronta), should in fact be transferred to the genus Solenopora Dybowski (Rhodophycophyta), A calcified reproductive layer was discovered in one of the specimens sectioned. These structures are interpreted as either sporangia or as sporangial chambers, and occur in a sorus rather than a conceptacle type of arrangement. This find has an important bearing on the phylogenetic history of the Solenoporaceae.
STRUCTURE OF THE ANISOGAMETES OF THE GREEN SIPHON PSEUDOBRYOPSIS SP. (CHLOROPHYTA)1
Authors: Roberts Keith R. , Stewart Kenneth D. , Mattox Karl R. 
Published: August 2007

ABSTRACTThe fine structure of the male and female gametes of Pseudobryopsis, particularly that of the flagellar apparatus, is compared with that of swarmers of other green algae. There is general similarity, with differences in detail, to the Ulvales and other green siphons that have been studied. The similarities include overlapping basal bodies, the capping plate type of connective between basal bodies, terminal caps, and system II fibrous roots (rhizoplasts). The capping plate of the female gamete differs from that in other green siphons and the Ulvales in form and in the presence of a faint striation. A diagram illustrating the actual arrangement of the components of the flagellar apparatus is given, along with a discussion of the fact that the mirror image of the true arrangement has been given in some reports on ulvaphycean algae.
PHOTOSYNTHETIC RESPONSE OF LAKE PLANKTON TO COMBINED NITROGEN ENRICHMENT1
Authors: Lean D. R. S. , Murphy T. P. , Pick F. R. 
Published: August 2007

ABSTRACTThe complex interplay between photosynthesis and the uptake of nitrogen was investigated in samples from five lakes of different size and trophic state. When enriched with 15NH4+, the photosynthetic rate was often reduced for 4–5 h in samples believed to be nitrogen deficient. This implies that energy was reallocated from photosynthesis to the uptake and assimilation of N. Stimulation in C uptake at low levels of NH4+ enrichment was followed by a progressive decline with further NH4+ enrichment. On other occasions when ambient NH4+ was undetectable, nutrient regeneration by zooplankton supplied a significant fraction of the required nitrogen. At these times and when the plankton had sufficient available N, there usually was no change in photosynthetic rate with either NH4+ or NO3−enrichment. Typically, little NO3− was taken up and no photosynthetic response was observed. On two occasions, however, the uptake of NO3− was significant due to high NO3− and low NH4+ levels early in the season. At one of these times there was a reduction in photosynthesis with NO3− enrichment. A further complication was observed when photosynthesis decreased with NH4+ enrichment but increased with NO3− enrichment despite negligible NO3− uptake. These observations illustrate that the complex metabolism of these two nitrogen sources is not fully understood. At optimum light intensity, C:N uptake ratios, even under NH4+ enrichment, are only sufficient to maintain the cellular C:N ratio unless much of the fixed C is respired or excreted. Three observations suggest that photosynthesis and N uptake are not coupled, (i) Photoinhibition of C uptake, but not N uptake was observed when low light adapted populations are exposed to high light conditions, (ii) The light intensity for maximum N uptake was slightly less than that for carbon. (iii) Dark N uptake was always near 50% of the maximum rate in the light whereas the C uptake was near 2% of Popt. Certainly, there is an interconnection because dark C uptake was enhanced by NH4+ enrichment.
EFFECTS OF GRAZERS AND ALGAL COMPETITORS ON FUCOID COLONIZATION IN TIDE POOLS1
Authors: Lubchenco Jane 
Published: August 2007

ABSTRACTIn New England, fucoids are conspicuously absent from midlittoral sheltered tide pools, though abundant on adjacent emergent rocks. Experimental removal of either herbivores or potential algal competitors from mid littoral tide pools failed to result in the establishment of fucoids. However, removal of both groups together resulted in the establishment of Fucus vesiculosus L. Once established, some individuals persisted for up to three years. These grew well, were of normal, healthy appearance and reproduced. The herbivores removed were Littorina littorea, L. obtusata and Acmaea testudinalis. Algae removed were Chondrus crispus Stackhouse, Ulva lactuca L., Rhizoclonium tortuosum Kützing, Spongomorpha spinescens Kützing, Polysiphonia sp., Dumontia incrassata (O.F. Muller) O. Kuntze and Scytosiphon lomentaria (Lyngbye) Link. It is concluded that absence of fucoids from mid littoral, protected pools is due to the joint action of herbivores and algal competitors and not to possible deleterious factors associated with constant submersion.
UPTAKE OF GUANINE BY THE DIATOM, PHAEODACTYLUM TRICORNUTUM1
Authors: Shah N. , Syrett P. J. 
Published: August 2007

ABSTRACTNitrate‐cultured cells of Phaeodactylum tricornutum Bohlin lack the ability to take up guanine but can do so after a period of nitrogen deprivation, i.e. photosynthesis in nitrogen‐free medium. Maximum rate of uptake occurred after 24 h of nitrogen deprivation. The development of ability to take up guanine required CO2 fixation and was prevented by cycloheximide, ammonium or nitrate. The guanine taken up accummulated in the cells almost entirely as a compound which is probably methylated hypoxanthine. Guanine uptake was dependent upon metabolism and exhibited Michaelis‐Menten like kinetics with a half‐saturation value of 0.48 ± 0.05 μM guanine and a maximum uptake rate for guanine of ca. 200 nmol · 10−8 cells · h−1. Rate of uptake increased hyperbolically with Na+ concentration, with 8.25 mM Na+ supporting half‐maximal rate, and it was inhibited by K+ ions.
Channel Coordination for a Supply Chain with a Risk‐Neutral Manufacturer and a Loss‐Averse Retailer*
Authors: Wang Charles X. , Webster Scott 
Published: August 2007

ABSTRACTThis articles considers a decentralized supply chain in which a single manufacturer is selling a perishable product to a single retailer facing uncertain demand. It differs from traditional supply chain contract models in two ways. First, while traditional supply chain models are based on risk neutrality, this article takes the viewpoint of behavioral principal–agency theory and assumes the manufacturer is risk neutral and the retailer is loss averse. Second, while gain/loss (GL) sharing is common in practice, there is a lack of analysis of GL‐sharing contracts in the supply chain contract literature. This article investigates the role of a GL‐sharing provision for mitigating the loss‐aversion effect, which drives down the retailer order quantity and total supply chain profit. We analyze contracts that include GL‐sharing‐and‐buyback (GLB) credit provisions as well as the special cases of GL contracts and buyback contracts. Our analytical and numerical results lend insight into how a manufacturer can design a contract to improve total supply chain, manufacturer, and retailer performance. In particular, we show that there exists a special class of distribution‐free GLB contracts that can coordinate the supply chain and arbitrarily allocate the expected supply chain profit between the manufacturer and retailer; in contrast with other contracts, the parameter values for contracts in this class do not depend on the probability distribution of market demand. This feature is meaningful in practice because (i) the probability distribution of demand faced by a retailer is typically unknown by the manufacturer and (ii) a manufacturer can offer the same contract to multiple noncompeting retailers that differ by demand distribution and still coordinate the supply chains.
Escalation: The Role of Problem Recognition and Cognitive Bias
Authors: Keil Mark , Depledge Gordon , Rai Arun 
Published: August 2007

ABSTRACTEscalation of commitment to a failing course of action is an enduring problem that remains central to the study of managerial behavior. Prior research suggests that escalation behavior results when decision makers choose to ignore negative feedback concerning the viability of a previously chosen course of action. Previous work has also suggested that certain cognitive biases might promote escalation behavior, but there has been little attempt to explore how biases other than framing affect escalation. In this article, we explore the extent to which decision makers actually perceive negative feedback as indicative of a problem and how this influences their decision to escalate. Although problem recognition and cognitive biases have been intensively studied individually, little is known about their effect on escalation behavior. In this research, we construct and test an escalation decision model that incorporates both problem recognition and two cognitive biases: selective perception and illusion of control. Our results revealed a significant inverse relationship between problem recognition and escalation. Furthermore, selective perception and illusion of control were found to significantly affect both problem recognition and escalation. The implications of these findings for research and practice are discussed. To improve problem recognition and reduce the incidence of escalation, practicing managers should implement modern project management practices that can help to identify and highlight potential problems while guarding against these two key cognitive biases that promote the behavior.
Internal Infrastructural Impacts on RFID Perceptions and Commitment: Knowledge, Operational Procedures, and Information‐Processing Standards
Authors: Bendoly Elliot , Citurs Alex , Konsynski Benn 
Published: August 2007

ABSTRACTFor many firms, radio frequency identification (RFID) suggests not only a new alternative to existing tracking methods but also a means to a range of previously cost‐prohibitive internal control and supply chain coordination innovations. In any event, and even in light of possible external pressures to adopt, the full potential of RFID for an individual firm must ultimately be viewed in consideration with the infrastructural capabilities of that firm. Furthermore, because adoption decisions are fundamentally based on managerial perceptions, it is critical to consider how certain forms of infrastructure provide the necessary transparency into other infrastructural characteristics to augment such decisions. We use multisource survey data in this work to consider several elements that contribute to this infrastructure and subsequently to perceptions of RFID benefit and actual commitment to adoption. Results demonstrate that the complementary effects of these infrastructural capabilities significantly impact both perceptions of and commitments to RFID.
Embeddedness of Organizational Capabilities*
Authors: Grewal Rajdeep , Slotegraaf Rebecca J. 
Published: August 2007

ABSTRACTManagers must regularly make decisions on how to access and deploy their limited resources in order to build organizational capabilities for a sustainable competitive advantage. However, failure to recognize that organizational capabilities involve complex and intricately woven underlying processes may lead to an incomplete understanding of how capabilities affect competitive advantage. As a means of understanding this underlying complexity, we discuss how managerial decisions on resource acquisition and deployment influence capability embeddedness and argue that capability embeddedness has an incremental effect on firm performance beyond the effects from organizational resources and capabilities. To investigate these issues, we present a hierarchical composed error structure framework that relies on cross‐sectional data (and allows for generalizations to panel data). We demonstrate the framework in the context of retailing, where we show that the embeddedness of organizational capabilities influences retailer performance above and beyond the tangible and intangible resources and capabilities that a retailer possesses. Our results illustrate that understanding how resources and capabilities influence performance at different hierarchical levels within a firm can aid managers to make better decisions on how they can embed certain capabilities within the structural and social relationships within the firm. Moreover, understanding whether the underlying objectives of the capabilities that are being built and cultivated have convergent or divergent goals is critical, as it can influence the extent to which the embedded capabilities enhance firm performance.
The Characteristics of Head Wounds Inflicted by “Humane Killer” (Captive‐Bolt Gun)—A 15‐Year Study*
Authors: Simic Milan , Draskovic Dragan , Stojiljkovic Goran , Vukovic Radenko , Budimlija Zoran M. 
Published: August 2007

Abstract:The “humane killer” or captive‐bolt gun, is the tool/weapon widely used in meat industry and private farmer households for slaughtering animal stock. Out of 17,250 autopsies performed at the Institute of Forensic Medicine in Novi Sad during the 15‐year period (1991–2005), 29 cases of suicides and two homicides were committed by captive‐bolt pistols. Wounds inflicted by captive‐bolt guns have specific morphological features, distinctive from wounds made by other kinds of hand firearms. Selected features of the captive‐bolt wounds (punched round entrance and a double pattern of smoke soiling) depend on distance and angle of instrument at the time of firing. Autopsy findings were compared with an experimental model consisting of 20 domestic pigs. Obtained results confirmed that the appearance of the entrance hole and soot deposits, along with differences in shape, location, extent, and density of soot blackening, could be useful in identification of weapon, direction of discharge, shooting distance, and angle of the muzzle to the frontal and sagittal planes of the head at the moment of fire.
Independence Day Explosion on Lovers Key*
Authors: Harding Brett A. , Wolf Barbara C. 
Published: August 2007

Abstract:The display of fireworks is a popular holiday celebration in the United States. Because injuries due to recreational fireworks‐related explosions among private consumers are relatively common, the sale of fireworks is regulated by the federal government and is also limited by state and local laws. In contrast, because fireworks display companies are under tight safety regulations, explosions in the professional pyrotechnics industry are uncommon occurrences, and the literature contains rare reports of injuries and fatalities resulting from such explosions. We report the 2003 Fourth of July commercial fireworks explosion on Lovers Key in southwest Florida that resulted in five fatalities. Events occurring during the investigation of the scene of this explosion illustrate the unique considerations and hazards for medicolegal death investigators, law enforcement and other investigative agencies. Additionally, this case demonstrates unusual aspects of the postmortem examinations performed on victims of fireworks‐related incidents.
The Analysis of Tire Rubber Traces Collected After Braking Incidents Using Pyrolysis‐Gas Chromatography/Mass Spectrometry
Authors: Sarkissian Garry 
Published: August 2007

Abstract:Automobile tire marks can routinely be found at the scenes of crime, particularly hit‐and‐run accidents and are left on road surfaces because of sudden braking or the wheels spinning. The tire marks are left due to the friction between the tire rubber and the solid road surface, and do not always demonstrate the tire tread pattern. However, the tire mark will contain traces of the tire. In this study, Pyrolysis Gas Chromatography/Mass Spectrometry was used to analyze 12 tires from different manufacturer’s and their traces collected after braking incidents. Tire marks were left on a conglomerate road surface with sudden braking. The samples were pyrolysed without removal of contaminant in a micro‐furnace type pyrolyser. Quantitative and qualitative analysis were performed on all the samples. All 12 samples were distinguished from each other. Each of the tire traces were identified as coming from there original source.
Studies of the Chronological Course of Wisdom Tooth Eruption in a Black African Population
Authors: Olze Andreas , Van Niekerk Piet , Schulz Ronald , Schmeling Andreas 
Published: August 2007

Abstract:The importance of forensic age estimation in living subjects has grown over the last few years. In dental age estimation, tooth eruption is a parameter of developmental morphology that can be analyzed by either clinical examination or by evaluation of dental X‐rays. In the present study, we determined the stage of wisdom tooth eruption in 410 male and 106 female Black South African subjects of known age (12–26 years) based on radiological evidence from 516 conventional orthopantomograms. Four eruption stages were determined (no emergence, alveolar emergence, gingival emergence, complete emergence). Statistical scores were determined for the individual stages separately for both sexes. The data presented here can be utilized for forensic estimation of the minimum and most probable ages of investigated persons.
A Comparison of Email Versus Letter Threat Contacts toward Members of the United States Congress*
Authors: Schoeneman‐Morris Katherine A. , Scalora Mario J. , Chang Grace H. , Zimmerman William J. , Garner Yancey 
Published: August 2007

Abstract:To better understand inappropriate correspondence sent to public officials, 301 letter cases and 99 email cases were randomly selected from the United States Capitol Police investigative case files and compared. Results indicate that letter writers were significantly more likely than emailers to exhibit indicators of serious mental illness (SMI), engage in target dispersion, use multiple methods of contact, and make a problematic approach toward their target. Emailers were significantly more likely than letter writers to focus on government concerns, use obscene language, and display disorganization in their writing. Also, letter writers tended to be significantly older, have more criminal history, and write longer communications. A multivariate model found that disorganization, SMI symptoms, problematic physical approach, and target dispersion significantly differentiated between the correspondence groups. The group differences illuminated by this study reveal that letter writers are engaging in behavior that is higher risk for problematic approach than are emailers.