1,113 research outputs found

    The Cultivation of Transformational Leadership In Secondary School Principals

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    Due to the challenges schools and school administrators face in the 21st century, transformational leadership is considered the most effective approach to school leadership (Bonsu & Twum-Danso, 2018; Longwell-McKean, 2012; Valentine & Prater, 2011). The purpose of this explanatory, sequential, mixed-methods study was to investigate the importance of cultivating transformational leadership qualities and traits within secondary school principals through professional development opportunities, networking experiences, and mentorships. There has been a lack of research on the need to train in transformational leadership and whether or not it positively influences follower outcomes (Peters, 2014; Tafvelin, 2013; Udin, 2020). Phase one data were collected from secondary school principals who were members of the Southwest Missouri Association of Secondary School Principals via a survey. Phase two focus group discussion questions were developed after analysis of survey responses. Analysis of focus group discussion data revealed five emergent themes: feedback, vulnerability, intentional relationships, professional growth, and COVID-19. Implications of this study include secondary school principals cultivating transformational leadership qualities and traits through one or more of the four components of transformational leadership; transformational leadership qualities and traits can be cultivated within secondary school principals through professional development, networking, and mentorships; and school districts should provide professional development, networking, and mentorship experiences for secondary school principals that focus on transformational leadership qualities and traits

    Parasites of the American White Pelican

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    Metazoan symbionts, including parasites, infecting the American white pelican (AWP) Pelecanus erythrorhynchos comprise a list of 75 species, 7 of which are new host records. Several new geographic records are also presented, but generally these have a low value because of the migratory nature of the bird. Evidence suggests that some parasites, mostly flies and other arthropods but also nematodes and digeneans, produce detrimental behavioral or pathologic changes in the AWP. Some of the arthropods transmit microbial agents to the pelican. Two digeneans that have the AWP as a definitive host harm and even kill their catfish intermediate host, especially in aquaculture, and another causes abnormalities and mortality in amphibians. Some of the arthropods with low host-specificity can potentially transmit harmful microbial agents to humans and domestic animals. A few avian bloodflukes, intestinal flukes, and nematodes can potentially cause “swimmers itch,” gastroenteritis, and “anisakiasis,” respectively, in humans. Because of the life cycles of some helminths, presence of those worms can provide an indication as to the dietary items of a specific pelican individual, where the individual has been, and how long it has been present in an area. Feather mites, lice, and diplostomoid digeneans serve as good parasites to indicate phylogenetic relationships among different pelican species as well as relationships among the Pelecanidae and other families such as the Sulidae

    A New Feather Mite Species of the Genus \u3ci\u3eTrouessartia\u3c/i\u3e Canestrini (Acariformes: Trouessartiidae) from the Northern Rough-winged Swallow \u3ci\u3eStelgidopteryx serripennis\u3c/i\u3e (Passeriformes: Hirundinidae) in Pennsylvania

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    A new feather mite species, Trouessartia stelgidopteryx sp. n. (Astigmata: Trouessartiidae), is described from the Northern rough-winged swallow Stelgidopteryx serripennis Newton (Passeriformes: Hirundinidae) in Pennsylvania, USA. The new species is close to the minutipes species group and differs from its representatives and all other known species of the genus Trouessartia in having a unique combination of features in males: the opisthosomal lobes are much longer than wide, they are separated by a large semi-ovate terminal cleft, and their lobar apices bear semi-ovate terminal lamellae with a smooth margin

    CSMA/RN: A universal protocol for gigabit networks

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    Networks must provide intelligent access for nodes to share the communications resources. In the range of 100 Mbps to 1 Gbps, the demand access class of protocols were studied extensively. Many use some form of slot or reservation system and many the concept of attempt and defer to determine the presence or absence of incoming information. The random access class of protocols like shared channel systems (Ethernet), also use the concept of attempt and defer in the form of carrier sensing to alleviate the damaging effects of collisions. In CSMA/CD, the sensing of interference is on a global basis. All systems discussed above have one aspect in common, they examine activity on the network either locally or globally and react in an attempt and whatever mechanism. Of the attempt + mechanisms discussed, one is obviously missing; that is attempt and truncate. Attempt and truncate was studied in a ring configuration called the Carrier Sensed Multiple Access Ring Network (CSMA/RN). The system features of CSMA/RN are described including a discussion of the node operations for inserting and removing messages and for handling integrated traffic. The performance and operational features based on analytical and simulation studies which indicate that CSMA/RN is a useful and adaptable protocol over a wide range of network conditions are discussed. Finally, the research and development activities necessary to demonstrate and realize the potential of CSMA/RN as a universal, gigabit network protocol is outlined

    Scalable parallel communications

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    Coarse-grain parallelism in networking (that is, the use of multiple protocol processors running replicated software sending over several physical channels) can be used to provide gigabit communications for a single application. Since parallel network performance is highly dependent on real issues such as hardware properties (e.g., memory speeds and cache hit rates), operating system overhead (e.g., interrupt handling), and protocol performance (e.g., effect of timeouts), we have performed detailed simulations studies of both a bus-based multiprocessor workstation node (based on the Sun Galaxy MP multiprocessor) and a distributed-memory parallel computer node (based on the Touchstone DELTA) to evaluate the behavior of coarse-grain parallelism. Our results indicate: (1) coarse-grain parallelism can deliver multiple 100 Mbps with currently available hardware platforms and existing networking protocols (such as Transmission Control Protocol/Internet Protocol (TCP/IP) and parallel Fiber Distributed Data Interface (FDDI) rings); (2) scale-up is near linear in n, the number of protocol processors, and channels (for small n and up to a few hundred Mbps); and (3) since these results are based on existing hardware without specialized devices (except perhaps for some simple modifications of the FDDI boards), this is a low cost solution to providing multiple 100 Mbps on current machines. In addition, from both the performance analysis and the properties of these architectures, we conclude: (1) multiple processors providing identical services and the use of space division multiplexing for the physical channels can provide better reliability than monolithic approaches (it also provides graceful degradation and low-cost load balancing); (2) coarse-grain parallelism supports running several transport protocols in parallel to provide different types of service (for example, one TCP handles small messages for many users, other TCP's running in parallel provide high bandwidth service to a single application); and (3) coarse grain parallelism will be able to incorporate many future improvements from related work (e.g., reduced data movement, fast TCP, fine-grain parallelism) also with near linear speed-ups

    Gonadal Maturation in the Cobia, Rachycentron canadum, from the Northcentral Gulf of Mexico

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    Gonadal maturation of cobia, Rachycentron canadum, was evaluated by examining 508 specimens from its recreational fishery. Specimens were collected off southeast Louisiana to northwest Florida by hook-and-line during February through October 1987-1991. Fork lengths (FL) of these fish ranged from 580-1,530 mm, with corresponding weights of 2.0-43.5 kg. The female:male ratio was 1:0.37. Using a combination of oocyte size frequency and histological assessment of many of the fish, we determined that females were ripe from May through September, with atretic oocytes occurring in some fish from July through October. Degenerating hydrated oocytes in July and October and the presence of resting ovaries in July suggest two major spawning periods; however, monthly gonosomatic indices peaking in May, followed by a steady decline, do not support that finding. Ovaries were placed into undeveloped, early developing, mid-developing , or late developing categories based upon oocyte size-frequency distributions. Developing ovaries had two or three modes of oocytes larger than 30 pm. Batch fecundity was estimated to be 2.6x106 to 1.91x108 oocytes, depending on the size of fish/ovaries. The smallest female with oocytes exhibiting vitellogenesis was 834 mm FL. This fish was 2 years old based its otolith evaluation. The smallest male with an abundance of spermatozoa in its testes was 640 mm FL and 1 year old based on otolith evaluation; smaller males were not examined. Females larger than 840 mm FL had vitellogenic oocytes in March and April. A few fish still had vitellogenic oocytes in early October, but none did by late October. When Gilson’s fluid was used to assess ovarian tissue, the fresh weight of the tissue was reduced by 20% after being stored for 3 months. The diameter of oocytes shrunk about 25% in Gilson’s fluid which was 11% less than those fixed in formalin, embedded in paraffin, and sectioned. Tissue sections from specific individuals, each demonstrating a variety of different developmental stages, were similar regardless of whether they were obtained from the anterior, middle, or posterior portion of either ovary

    Phylogenetic Afficity of \u3ci\u3eGenolopa\u3c/i\u3e (Digenea: Monorchiidae) With Descriptions of Two New Species

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    The validity of Genolopa Linton, 1910 has been controversial because the observation of presently recognized critical diagnostic morphological features (spines in the genital atrium and a bipartite, anteriorly spined terminal organ) were omitted from the original diagnosis, and these features were not universally appreciated as important diagnostic features until 2008. Modern taxonomists have been further challenged by inappropriate fixation techniques that have resulted in various interpretations of morphological features. Consequently, named species in the genus have fluctuated among other monorchiid genera depending on various interpretations by taxonomists, and a modern consensus on classifying these species is lacking. This study combines a molecular approach with modern conventional morphological techniques to investigate the validity of Genolopa as a lineage within the Monorchiidae. New morphology and molecular sequence data from the type-species of Genolopa were studied, and two new species in the genus were described, Genolopa vesca n. sp. and Genolopa minuscula n. sp. Interrelationships among the Monorchiidae were explored using Bayesian inference analysis of the partial 28S rDNA fragment, incorporating three species of Genolopa for the first time. The phylogenetic analysis revealed that the genus represents a natural lineage, supporting the presence of spines in the genital atrium in conjunction with a bipartite and anteriorly spined terminal organ as key features of the generic diagnosis. This study also provides for the first time partial 28S rDNA data for Postmonorchis orthopristis, Lasiotocus trachinoti, Lasiotocus glebulentus, and an unidentified species of Lasiotocus

    A Review of \u3ci\u3ePolylekithum Arnold\u3c/i\u3e, 1934 and Its Familial Affinities Using Morphological and Molecular Data, With Description of \u3ci\u3ePolylekithum catahoulensis\u3c/i\u3e sp nov.

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    The type material of Polylekithum ictaluri, P. halli, and Maculifer chandleri was examined from the United States National Parasite Museum, and we determined that the material was conspecific, making P. halli and M. chandleri junior subjective synonyms of P. ictaluri. Polylekithum catahoulensis sp. nov. was described from material collected from catfishes at the Catahoula Wildlife Refuge, LaSalle Parish, Louisiana, USA, and compared with P. ictaluri collected from catfishes in Reelfoot Lake, Obion County, Tennessee, USA, and the Pearl River, Hancock County, Mississippi, USA. Polylekithum catahoulensis had smaller eggs (77–88 μm long by 51–63 μm wide vs. 94–108 μm by 52–76 μm) and a longer forebody (35–41% of overall body length vs. 29–34%). Comparison of more than 2,400 bp long fragments of nuclear ribosomal DNA (complete ITS and partial 28S regions) strongly supported the status of P. catahoulensis as a new species. Molecular phylogenetic analysis of 28S rDNA gene sequences from Polylekithum as well as representative species from Allocreadiidae, Atractotrematidae, Brachycoeliidae, Callodistomidae, Dicrocoeliidae, Encyclometridae, Gorgoderidae, Haploporidae, Opecoelidae, Plagiorchiidae, and Telorchiidae rooted by Monorchiidae and Lissorchiidae demonstrated that of the families tested, Polylekithum was most closely related to Encyclometridae as a gorgoderoid and not to Allocreadiidae as previously reported. Morphological features of three South American allocreadiids, Allocreadium patagonicum, P. percai, and A. pichi were inconsistent with generic diagnoses of Allocreadium and Polylekithum, so we suggested they belonged in a single unnamed genus similar to Creptotrema. Polylekithum catlai from India was assessed from the description and failed to conform to the generic diagnosis of Polylekithum. Morphology of Caudouterina suggested a close relationship with Polylekithum and not Allocreadiidae

    Infectivity and Pathogenicity of \u3ci\u3eBaculovirus penaei\u3c/i\u3e (BP) in Cultured Larval and Postlarval Pacific White Shrimp, \u3ci\u3ePenaeus vannamei\u3c/i\u3e, Related to the Stage of Viral Development

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    The infectivity and pathogenicity of the penaeid shrimp virus, Baculovirus penaei (BP), is influenced by the stage of viral development. This study consisted of a preliminary experiment which showed that nonoccluded virus administered per os is infective, followed by two infectivity experiments. In the first phase of each infectivity experiment, mysis stage larvae of Penaeus vannamei were inoculated with BP and samples of infected tissue were collected at various times postinoculation (p.i.). These samples were then used to inoculate either mysis or postlarval stage P. vannamei in the second phase of each experiment. Viral inocula prepared from patently infected tissues consistently produced infections in both mysis and postlarval stage shrimp. Inocula prepared from prepatently infected tissue collected 12–18 h p.i. produced infections in some but not all replicate cultures, while inocula prepared from tissues collected earlier than 12 h p.i. were not infective. Viral development in mysis stage larvae was substantially delayed and the mortality was significantly lower when the viral inocula were prepared from prepatently compared to patently infected tissues. BP appears to be most pathogenic to larvae that have been exposed to inocula prepared from tissues that had recently developed a high prevalence of patent infections or about 72 h p.i
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