105 resultados para feelings towards mathematics
Resumo:
Sea-finding behavior in sea turtle hatchlings is modified by the visual cues provided by artificial beach front lighting. The consequent landward movement of hatchlings in response to coastal electric lighting reduces their survival rates. We assessed the potential impact of coastal lighting at Rushikulya, an important mass nesting site of the olive ridley sea turtle (Lepidochelys olivacea) in the Indian Ocean region. We examined the response of hatchlings to light characteristics in an experimental setup, as well as to the existing lighting regimes along the beach, using arena trials. Previous studies on other species indicate preferential orientation towards low wavelength and high intensity light. Our study confirms these preferences among hatchlings from the Indian Ocean population of olive ridleys. In addition we also found that wavelength and intensity could have an interactive effect upon hatchling orientation. Hatchlings at the study site respond both to visible point sources of light and to sheer glows of light. Though beach plantations of introduced Casuarina equisetifolia are generally considered to have negative impacts on sea turtle nesting beaches, we found that they acted as an effective light barrier when planted about 50 m away from the high tide line. We developed a model of the expected impact of artificial lighting on hatchling orientation during mass hatching events of previous years, and predict as much as 50% misorientation in some years. We also developed a map representing the misorientation of hatchlings due to artificial lighting based on arena trials in different regions of the beach. The results of the study helped identify focal areas for light management on the beach, which could be critical for the survival of this population.
Resumo:
Birefringent composite models are fabricated using epoxy resin reinforced with unidirectionally oriented glass fibers. The mechanical and photoelastic properties of the material at room temperature are determined. To explore the possibility of application of stress-freezing technique to birefringent composite models, the behavior and properties of this material are studied at elevated temperature (at stress-freezing temperature of the resin). The properties of the material at room and at elevated temperatures are reported. The feasibility of stress freezing glass-fiber-reinforced epoxy composites with low-fiber-volume fraction is discussed.
Resumo:
A conformationally locked tetraacetate undergoes, quite akin to a temperature-guided molecular switch, a reversible thermal switching between two polymorphic modifications; the room-temperature alpha-form converted at -4 degrees C to a low-temperature denser beta-form, which displayed an unusual kinetic stability till 67 degrees C and transformed back to the alpha-form beyond this temperature.
Resumo:
A key issue on achieving sustainability and sustainable development is through administrative reforms. The book under review, a compilation of ‘good practices’, comes in at a time when the helm of affairs on governance and administrative practices is up for a thorough introspection. This book is a collection of papers presented at the ‘International Conference on Administrative Reforms, Good Practices and their Sustainability’ on 24–25th April 2003 at New Delhi.
Resumo:
As editors of the book Lilavati's Daughters: The Women Scientists of India, reviewed by Asha Gopinathan (Nature 460, 1082; 2009), we would like to elaborate on the background to its title. Lilavati was a mathematical treatise of the twelfth century, composed by the mathematician and astronomer Bhaskaracharya (1114–85) — also known as Bhaskara II — who was a teacher of repute and author of several other texts. The name Lilavati, which literally means 'playful', is a surprising title for an early scientific book. Some of the mathematical problems posed in the book are in verse form, and are addressed to a girl, the eponymous Lilavati. However, there is little real evidence concerning Lilavati's historicity. Tradition holds that she was Bhaskaracharya's daughter and that he wrote the treatise to console her after an accident that left her unable to marry. But this could be a later interpolation, as the idea was first mentioned in a Persian commentary. An alternative view has it that Lilavati was married at an inauspicious time and was widowed shortly afterwards. Other sources have implied that Lilavati was Bhaskaracharya's wife, or even one of his students — raising the possibility that women in parts of the Indian subcontinent could have participated in higher education as early as eight centuries ago. However, given that Bhaskara was a poet and pedagogue, it is also possible that he chose to address his mathematical problems to a doe-eyed girl simply as a whimsical and charming literary device.
Resumo:
Along with useful microorganisms, there are some that cause potential damage to the animals and plants. Detection and identification of these harmful organisms in a cost and time effective way is a challenge for the researchers. The future of detection methods for microorganisms shall be guided by biosensor, which has already contributed enormously in sensing and detection technology. Here, we aim to review the use of various biosensors, developed by integrating the biological and physicochemical/mechanical properties (of tranducers), which can have enormous implication in healthcare, food, agriculture and biodefence. We have also highlighted the ways to improve the functioning of the biosensor.
Resumo:
Coupled electromagnetically induced transparency (EIT) has been observed with a dual mode control laser. The technique can be used for generating EIT-comb from optical frequency comb.
Resumo:
Isoquinoline was prepared through the Beckmann rearrangement of cinnamaldoxime over different H-zeolites, K-10 montmorillonite clay, amorphous SiO2–Al2O3 and γ-alumina under well-optimized conditions of temperature, weight hourly space velocity and catalyst loading. Cinnamaldoxime under ambient reaction conditions over the catalysts underwent migration of the anti-styryl moiety to electron deficient nitrogen (Beckmann rearrangement) followed by an intramolecular cyclization to yield isoquinoline. Cinnamo-nitrile (dehydration product) and cinnamaldehyde were formed as by-products. Isoquinoline formation was high on zeolite catalysts (ca. >86.5%) and mordenite (ca. 92.3%) was the most efficient in the series. Catalysts were susceptible for deactivation and the decrease in the percentage conversion of oxime with time is associated with a corresponding increase in the acid hydrolysis producing salicylaldehyde at later stages of the reaction. However, these catalysts retain activity considerably and can be recycled without loss of activity and change of product distribution.
Resumo:
One influential image that is popular among scientists is the view that mathematics is the language of nature. The present article discusses another possible way to approach the relation between mathematics and nature, which is by using the idea of information and the conceptual vocabulary of cryptography. This approach allows us to understand the possibility that secrets of nature need not be written in mathematics and yet mathematics is necessary as a cryptographic key to unlock these secrets. Various advantages of such a view are described in this article.
Resumo:
A new family of surf ace-modified carbohydrates with locked, axial-rich conformations and bipolarofacial architectures has been developed with the aid of carbocyclic ring annulation. These novel trans-decalin-based carbohydrates have been synthesized, from simple aromatic precursors such as tetralin, through the ozonolysis of an appropriately protected allylic alcohol, followed by a cascade of intramolecular acetalizations to generate the sugar pyran moiety. The stereoselective synthesis of (racemic) cyclohexane-annulated 0-glucopyranoside and a-glucofuranoside from a common annulated trans-cyclohexadiene diol (trans-CHD) precursor under-scores the versatility of our approach. The efficacy of the annulation stratagem in generating carbohydrate diversity has been demonstrated through the synthesis of two regioisomeric annulated gulose derivatives, which differ only in the site of ring annulation on the sugar moiety. The mapping of the MLP surface and solid-state architecture of the new sugar shows that cycloalkane annulation results in surface modification and fine-tuning of sugar hydrophilicity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).
Resumo:
A new family of surf ace-modified carbohydrates with locked, axial-rich conformations and bipolarofacial architectures has been developed with the aid of carbocyclic ring annulation. These novel trans-decalin-based carbohydrates have been synthesized, from simple aromatic precursors such as tetralin, through the ozonolysis of an appropriately protected allylic alcohol, followed by a cascade of intramolecular acetalizations to generate the sugar pyran moiety. The stereoselective synthesis of (racemic) cyclohexane-annulated 0-glucopyranoside and a-glucofuranoside from a common annulated trans-cyclohexadiene diol (trans-CHD) precursor under-scores the versatility of our approach. The efficacy of the annulation stratagem in generating carbohydrate diversity has been demonstrated through the synthesis of two regioisomeric annulated gulose derivatives, which differ only in the site of ring annulation on the sugar moiety. The mapping of the MLP surface and solid-state architecture of the new sugar shows that cycloalkane annulation results in surface modification and fine-tuning of sugar hydrophilicity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).
Resumo:
By a series of reactions the Diels-Alder adduct IV of maleic anhydride and β-trans-Ocimene gave 1-hydroxy-1,4-dimethyl-7-hydroxymethyloctahydroindane (XII). Its further synthetic elaboration furnished 1,4-dimethyl-7-(2-ethoxycarbonyl-1-propenyl)-Δ1-octahydroindane of the valerenic acid skeleton.