Spectral Classification; Old and Contemporary

Beginning with a historical account of the spectral classification, its refinement through additional criteria is presented. The line strengths and ratios used in two dimensional classifications of each spectral class are described. A parallel classification scheme for metal-poor stars and the standards used for classification are presented. The extension of spectral classification beyond M to L and T and spectroscopic classification criteria relevant to these classes are described. Contemporary methods of classifications based upon different automated approaches are introduced.Comment: To be published in "Principles and Perspectives in Cosmochemistry" Lecture Notes on Kodai School on Synthesis of Elements in Stars: Ed Aruna Goswami & Eswar Reddy, Springer Verlag, 2009, 17 pages, 10 figure

The Role of Entrepreneur-Venture Fit in Online Home-based Entrepreneurship: A Systematic Literature Review

Home-based businesses and their founders represent an important, but under-researched facet of entrepreneurship. Far from being small, hobby-businesses with little economic impact, home-based business make significant contribution to national economies in terms of both turnover and employment. Online home-based businesses have been recognised as an important and distinct sector of the home-based business domain, offering unique opportunity for innovation and business diversity. The paper presents a systematic literature review of extant research on online home-based entrepreneurs and their businesses. The findings of the review are structured and discussed using the theoretical lens of entrepreneur-venture fit. Use of this lens allows the study to bring coherence to previously fragmented extant studies, providing a basis for future research in this domain. The study also develops a novel model of entrepreneur-venture fit in the specific case of online home-based businesses. This allows us to suggest five positive interactions between entrepreneurial and venture characteristics. It also allows us to suggest a number of previously unidentified negative interactions, which may result in entrepreneurs becoming ‘locked-in’ and suffering multiple sources of stress

Estrogen/progesterone Receptor and HER2 Discordance Between Primary Tumor and Brain Metastases in Breast Cancer and Its Effect on Treatment and Survival

BACKGROUND: Breast cancer treatment is based on estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal growth factor receptor 2 (HER2). At the time of metastasis, receptor status can be discordant from that at initial diagnosis. The purpose of this study was to determine the incidence of discordance and its effect on survival and subsequent treatment in patients with breast cancer brain metastases (BCBM). METHODS: A retrospective database of 316 patients who underwent craniotomy for BCBM between 2006 and 2017 was created. Discordance was considered present if the ER, PR, or HER2 status differed between the primary tumor and the BCBM. RESULTS: The overall receptor discordance rate was 132/316 (42%), and the subtype discordance rate was 100/316 (32%). Hormone receptors (HR, either ER or PR) were gained in 40/160 (25%) patients with HR-negative primary tumors. HER2 was gained in 22/173 (13%) patients with HER2-negative primary tumors. Subsequent treatment was not adjusted for most patients who gained receptors-nonetheless, median survival (MS) improved but did not reach statistical significance (HR, 17-28 mo, P = 0.12; HER2, 15-19 mo, P = 0.39). MS for patients who lost receptors was worse (HR, 27-18 mo, P = 0.02; HER2, 30-18 mo, P = 0.08). CONCLUSIONS: Receptor discordance between primary tumor and BCBM is common, adversely affects survival if receptors are lost, and represents a missed opportunity for use of effective treatments if receptors are gained. Receptor analysis of BCBM is indicated when clinically appropriate. Treatment should be adjusted accordingly. KEY POINTS: 1. Receptor discordance alters subtype in 32% of BCBM patients.2. The frequency of receptor gain for HR and HER2 was 25% and 13%, respectively.3. If receptors are lost, survival suffers. If receptors are gained, consider targeted treatment

Conspicuous Female Ornamentation and Tests of Male Mate Preference in Threespine Sticklebacks (Gasterosteus aculeatus)

Sexual selection drives the evolution of exaggerated male ornaments in many animal species. Female ornamentation is now acknowledged also to be common but is generally less well understood. One example is the recently documented red female throat coloration in some threespine stickleback (Gasterosteus aculeatus) populations. Although female sticklebacks often exhibit a preference for red male throat coloration, the possibility of sexual selection on female coloration has been little studied. Using sequential and simultaneous mate choice trials, we examined male mate preferences for female throat color, as well as pelvic spine color and standard length, using wild-captured threespine sticklebacks from the Little Campbell River, British Columbia. In a multivariate analysis, we found no evidence for a population-level mate preference in males, suggesting the absence of directional sexual selection on these traits arising from male mate choice. Significant variation was detected among males in their preference functions, but this appeared to arise from differences in their mean responsiveness across mating trials and not from variation in the strength (i.e., slope) of their preference, suggesting the absence of individual-level preferences as well. When presented with conspecific intruder males, male response decreased as intruder red throat coloration increased, suggesting that males can discriminate color and other aspects of phenotype in our experiment and that males may use these traits in intrasexual interactions. The results presented here are the first to explicitly address male preference for female throat color in threespine sticklebacks.Open Access Publishing Fun

Some of the earliest depictions of the human spine: a glimpse into European history.

INTRODUCTION: Drawings of the human form have a history almost as old as mankind itself. However, illustrations of the human spine as seen with the vertebral column were not seen until much later. This paper reviews some of the early European depictions of the human vertebral column from the twelfth (e.g., Fünfbilderserie Bone-Man : 1152 A.D.) and thirteenth (e.g., Ashmole 1292) centuries. Man\u27s understanding of his body has evolved over hundreds of years. CONCLUSIONS: This glimpse into our past and early drawings of the human spine illustrate how this particular anatomical structure was perceived almost a millennium ago and would not be structurally correct renditions until Leonardo da Vinci in the fifteenth century

Professionals' attitudes towards the use of cognitive enhancers in academic settings.

Introduction and aimsThe non-medical use of prescription stimulants such as methylphenidate, dexamphetamine and modafinil is increasing in popularity within tertiary academic settings. There is a paucity of information on awareness, attitudes, and acceptability by professionals of use in this context. This study aimed to investigate professionals' knowledge of and attitudes towards the use of cognitive enhancers (CEs) in academic settings, and their willingness to use a hypothetical CE.Design and methodsA mail survey was sent to doctors, pharmacists, nurses, accountants and lawyers in New Zealand. These disciplines were chosen as they require professional registration to practice. The questionnaire comprised four sections: (1) demographics, (2) knowledge of CEs, (3) attitudes towards the use of CEs, and (4) willingness to use hypothetical CEs.ResultsThe response rate was 34.5% (414/1200). Overall, participants strongly disagreed that it was fair to allow university students to use CEs for cognitive enhancement (Mdn = 1, IQR: 1,3), or that it is ethical for students without a prescription to use cognitive enhancers for any reason (Mdn = 1, IQR: 1,2). Professions differed in their attitudes towards whether it is ethical for students without a prescription to use CEs for any reason (p = 0.001, H 31.527).Discussion and conclusionDivergent views and lack of clear consensus within professions and between professionals on the use of CEs have the potential to influence both professionals and students as future professionals. These divergent views may stem from differences in the core values of self-identity as well as extrinsic factors of acceptability within the profession in balancing the elements of opportunity, fairness and authenticity in cognitive enhancement. Further research is required to inform the development of policy and guidelines that are congruent with all professions

Lumbar Facet Tropism: A Comprehensive Review.

BACKGROUND: Scattered reports exist in the medical literature regarding facet tropism. However, this finding has had mixed conclusions regarding its origin and impact on the normal spine. METHODS: We performed a literature review of the anatomy, embryology, biomechanics, and pathology related to lumbar facet tropism. RESULTS: Facet tropism is most commonly found at L4-L5 vertebral segments and there is some evidence that this condition may lead to facet degenerative spondylolisthesis, intervertebral disc disease, and other degenerative conditions. CONCLUSION: Long-term analyses of patients are necessary to elucidate relationships between associated findings and facet tropism. In addition, a universally agreed definition that is more precise should be developed for future investigative studies