Crippling Strength of Axially Loaded Rods

A new empirical formula was developed that holds good for any length and any material of a rod, and agrees well with the results of extensive strength tests. To facilitate calculations, three tables are included, giving the crippling load for solid and hollow sectioned wooden rods of different thickness and length, as well as for steel tubes manufactured according to the standards of Army Air Services Inspection. Further, a graphical method of calculation of the breaking load is derived in which a single curve is employed for determination of the allowable fiber stress. Finally, the theory is discussed of the elastic curve for a rod subject to compression, according to which no deflection occurs, and the apparent contradiction of this conclusion by test results is attributed to the fact that the rods under test are not perfectly straight, or that the wall thickness and the material are not uniform. Under the assumption of an eccentric rod having a slight initial bend according to a sine curve, a simple formula for the deflection is derived, which shows a surprising agreement with test results. From this a further formula is derived for the determination of the allowable load on an eccentric rod. The resulting relations are made clearer by means of a graphical representation of the relation of the moments of the outer and inner forces to the deflection

Presence and properties of cellulase and hemicellulase enzymes of the gecarcinid land crabs Gecarcoidea natalis and Discoplax hirtipes.

Digestive juice from the herbivorous gecarcinid land crabs Gecarcoidea natalis and Discoplax hirtipes exhibited total cellulase activity and activities of two cellulase enzymes; endo-&szlig;-1,4-glucanase and &szlig;-1,4-glucosidase. These enzymes hydrolysed native cellulose to glucose. The digestive juice of both species also contained laminarinase, licheninase and xylanase, which hydrolysed laminarin, lichenin and xylan, respectively, to component sugars. The pH optima of &szlig;-1,4-glucosidase, endo-&szlig;-1,4-glucanase and total cellulase from G. natalis were 4&ndash;5.5, 5.5 and 5.5&ndash;7, respectively. In the digestive juice from D. hirtipes, the corresponding values were 4&ndash;7, 5.5&ndash;7 and 4&ndash;9, respectively. The pH of the digestive juice was 6.69&plusmn;0.03 for G. natalis and 6.03&plusmn;0.04 for D. hirtipes and it is likely that the cellulases operate near maximally in vivo. In G. natalis, total cellulase activity and endo-&szlig;-1,4-glucanase activity were higher than in D. hirtipes, and the former species can thus hydrolyse cellulose more rapidly. &szlig;-1,4-glucosidase from G. natalis was inhibited less by glucono-D-lactone (Ki=11.12 mmol l-1) than was the &szlig;-1,4-glucosidase from D. hirtipes (Ki=4.53 mmol l-1). The greater resistance to inhibition by the &szlig;-1,4-glucosidase from G. natalis may contribute to the efficiency of the cellulase system in vivo by counteracting the effects of product inhibition and possibly dietary tannins. The activity of &szlig;-1,4-glucosidase in the digestive juice of D. hirtipes was higher than that of G. natalis.<br /

Osservazioni sul concetto di "Giorno Natalizio" nel mondo greco e romano e sull'espressione di Seneca dies aeterni natalis

The article begins with an excursus on the concept of "birthday" in the graeco-roman pagan world and on the celebrations of this day. The second point is an analysis of rlμhpa yEvÉOXios- dies natalis - in early Christian literature, where it often means the day of death and presents an inversion of significance if compared with the current pagan use. Finally, the authoress deals with the Senecan expression dies aeterni natalis (Ep. CII 26), which is referred not to the birthday, but to the day of death.Este artículo comienza con un paréntesis en el concepto de ‘’cumpleaños’’ en el mundo greco-romano pagano y en las celebraciones de este día. El segundo punto es un análisis de rlμhpa yEvÉOXios- dies natalis – en la literatura cristiana temprana, donde a menudo significa el día de la muerte y presenta una inversión del significado si se compara con el actual uso pagano. Finalmente, la autora lidia con la expresión de Séneca dies aeterni natalis (Ep. CII 26), que se refiere no solo al cumpleaños sino también al día de la muerte

Body-size dependent foraging strategies in the Christmas Island flying-fox : implications for seed and pollen dispersal within a threatened island ecosystem

Background: Animals are important vectors for the dispersal of a wide variety of plant species, and thus play a key role in maintaining the health and biodiversity of natural ecosystems. On oceanic islands, flying-foxes are often the only seed dispersers or pollinators. However, many flying-fox populations are currently in decline, particularly those of insular species, and this has consequences for the ecological services they provide. Knowledge of the drivers and the scale of flying-fox movements is important in determining the ecological roles that flying-foxes play on islands. This information is also useful for understanding the potential long-term consequences for forest dynamics resulting from population declines or extinction, and so can aid in the development of evidence-based ecological management strategies. To these ends, we examined the foraging movements, floral resource use, and social interactions of the Critically Endangered Christmas Island flying-fox (Pteropus natalis). Methods: Utilization distributions, using movement-based kernel estimates (MBKE) were generated to determine nightly foraging movements of GPS-tracked P. natalis (n = 24). Generalized linear models (GLMs), linear mixed-effect models (LMMs), and Generalized linear mixed-effects model (GLMMs) were constructed to explain how intrinsic factors (body mass, skeletal size, and sex) affected the extent of foraging movements. In addition, we identified pollen collected from facial and body swabs of P. natalis (n = 216) to determine foraging resource use. Direct observations (n = 272) of foraging P. natalis enabled us to assess the various behaviors used to defend foraging resources. Results: Larger P. natalis individuals spent more time foraging and less time traveling between foraging patches, traveled shorter nightly distances, and had smaller overall foraging ranges than smaller conspecifics. Additionally, larger individuals visited a lower diversity of floral resources. Conclusions: Our findings suggest that smaller P. natalis individuals are the primary vectors of long-distance dispersal of pollen and digested seeds in this species, providing a vital mechanism for maintaining the flow of plant genetic diversity across Christmas Island. Overall, our study highlights the need for more holistic research approaches that incorporate population demographics when assessing a species’ ecological services

La qualità della formazione: il corso di Alta Formazione in "Conservazione, gestione e catalogazione delle raccolte e collezioni in archivi, biblioteche, musei"

none2noneS. Lorusso; A. NataliS. Lorusso; A. Natal

Ichthyofaunal Diversification and Distribution in the Big Creek Watershed, Craighead and Greene Counties, Arkansas

Big Creek is a relatively small deltaic stream, in northeastern Arkansas, in an area of intense cultivation. Recently it has been dredged in the interest of flood control. Lost Creek and Mud Creek are the major tributaries of Big Creek and collectively drain the Big Creek watershed. The streams were found to have relatively low alkalinity, moderate carbon dioxide, adequate oxygen values, and relatively high turbidity. Channeling of Big Creek and Lost Creek has effectively destroyed distinct pool-riffle biocies and reduced the number of acceptable spawning areas. Lost Creek, also, receives effluent from residential dwellings, a secondary treatment sewage plant, and a meat rendering plant. Mud Creek, in the absence of channeling and deleterious effects of effluents, provided a relatively greater diversity of habitat than did Big Creek or Lost Creek

BRANDING AWARENESS LOGO 39th POLMED

Branding adalah berbagai kegiatan komunikasi yang dilakukan oleh siapapun pemilik merk (baik dalam kategori bisnis, organisasi, layanan masyarakat, lembaga pemerintah ataupun pendidikan). Branding bukanlah sekadar aktivitas biasa. Namun juga sebagai sarana dalam meningkatkan kesadaran merk dari sebuah organisasi. Politeknik Negeri Medan yang pada tahun 2021 menyambut Dies Natalis ke-39, merupakan momentum yang tepat untuk dilakukan program Branding yang juga bersamaan dengan spirit Lembaga melakukan berbagai kegiatan persiapan menuju akreditasi unggul dan berubah menjadi Perguruan Tinggi Badan Layanan Umum (PTN-BLU). Penelitian ini bertujuan untuk menghasilkan informasi visual yang sesuai dan tepat sasaran pada momentum Dies Natalis 39 Tahun Politeknik Negeri Medan. Dies Natalis yang selalu bertambah umur, juga harus dicitrakan sebagai pembeda setiap tahunnya

Rondot Natalis

Notice sur NATALIS RONDOT pour le DICTIONNAIRE CRITIQUE DES HISTORIENS DE L'ART DU XIXE SIECLE qui sera publié en ligne sur le site de l'INHA (Institut National d'Histoire de l'Art-Paris) en 2009..Grand travailleur, érudit, esprit curieux, voyageur, doué, de plus, d'une belle aisance de plume, Rondot ne se consacre aux études concernant l'art et les artistes qu'après avoir mis un terme à sa carrière en 1869. La multiplicité de ses activités révèle la richesse de ses capacités, la diversité autant que l'étendue de ses centres d'intérêt, ce dont témoigne sa bibliographie. Celle-ci (exclusion faite des centaines d'articles fournis pour des journaux ou des dictionnaires) est pour moitié consacrée aux questions artistiques

Ichthyofaunal Diversification and Distribution in the Ozark Stream in Northcentral Arkansas

The distribution and diversity of the ichthyofauna of Arkansas are poorly known. This study is part of a continuing effort to elucidate the natural history of Arkansas. Big Creek is a relatively small, clear, cool-water stream in the Ozark Plateau of northcentral Arkansas. Big Creek and its tributaries drain into Lake Norfork, an impoundment on North Fork River. A total of 6,779 fish of 30 species was collected. Dominant pool species included Notropis boops, Fundulus catenatus, F. olivaceus, Labidesthes sicculus, and Campostoma anomalum; dominant riffle species included Etheostoma spectabile, E. caeruleum, Notropis boops, Fundulus catenatus, and Campostoma anomalum. The numerical standing crop ranged from 1.3 to 2.6 fish/m 2 in the pools and riffles, respectively. The relative uniformity of substrate and soil types throughout the watershed, and the absence of rooted aquatic plants, limited the diversity of species found. The concomitant reduction in competition and predation probably explains the relatively large numerical standing crop

Profil Proses Berpikir Siswa dalam Pemecahan Masalah Matematika Ditinjau dari Gaya Kognitif. (Dibimbing oleh Abdul Rahman dan Awi Dassa).

Penelitian ini bertujuan untuk mendeskripsikan profil proses berpikir siswa dalam pemecahan masalah yang ditinjau dari gaya kognitif, yaitu gaya kognitif field independent dan field dependent. Penelitian ini merupakan penelitian deskriptif dengan pendekatan kualitatif yang dilaksanakan di SMP Negeri 23 Makassar. Subjek dalam penelitian ini sebanyak 2 orang siswa kelas VIII yang terdiri dari 1 orang subjek gaya kognitif field independent dan 1 orang subjek gaya kognitif field dependent. Tes pemecahan masalah yang diberikan sebanyak dua nomor yaitu, masalah I pada Materi SPLDV dan masalah II pada materi tentang Sudut dan Garis. Hasil penelitian menunjukan, pada tahap memahami masalah, untuk masalah I dan II, proses berpikir yang ditampilkan oleh subjek FI dan FD cendrung sama yaitu menerima informasi dengan cara membaca soal dengan teliti. Mengolah informasi yang ditunjukan dengan mengetahui inti masalah pada soal. Memanggil kembali informasi yang ditandai dengan menyatakan informasi yang diketahui dan ditanyakan dengan bahasanya sendiri. Pada tahap merencanakan pemecahan, untuk masalah I, subjek FI dan subjek FD cendrung sama. Sedangkan untuk masalah II terdapat perbedaan. Subjek FD tidak dapat memanggil kembali semua informasi lama yang telah diterimanya sehingga tidak dapat melakukan pengolahan informasi dengan tepat untuk memecahkan masalah. Pada tahap melaksanakan rencana pemecahan, untuk masalah I, perbedaan yang ditampilkan adalah subjek FI cendrung lebih kreatif dalam mengolah informasi daripada subjek FD. Sedangkan untuk masalah II, subjek FI lebih baik dalam mengolah dan mengambil kembali informasi dari pada subjek FD. Pada tahap melihat kembali, subjek FI melakukan pengolahan dan penyimpanan informasi sedangkan subjek FD tanpa mengolah informasi yang telah diperoleh. Kata Kunci: Proses Berpikir, Pemecahan Masalah, Gaya Kogniti