Shedding in the Timber Rattlesnake: Natural Patterns, Endocrinological Underpinnings, Temporal and Energetic Effort, and Integration as a Reptilian Life History Trait

The semi-frequent replacement of the epidermis (ecdysis) is a characteristic trait of reptiles. Whereas all reptiles regularly engage in some degree of skin shedding, skin morphology in snakes necessitates the synchronous replacement of the entire epidermis and facilitates the subsequent removal of the old layer as a single sheet. To date, the ubiquitous process has garnered little attention from researchers because snakes shed with unpredictable timing and frequency and are exceedingly cryptic during ecdytic cycles; previously impeding detailed physiological or ecological investigations of the process in the clade. Because of the lack of study, ecdysis is often viewed as a maintenance function; occurring whenever change in body size necessitates the generation of a new epidermal layer. However, recent observations that skin shedding plays a role in conspecific sexual signaling in some snakes suggest that the predominate view of ecdysis as a growth function may be overly simplistic. By studying population-scale patterns of shed, I was able to describe the timing and frequency of ecdysis in a population of Timber Rattlesnakes, solving a long-standing problem in continued study of ecdysis; predicting the occurrence of shed events. Coupling my knowledge of patterns of shed timing with novel methodologies for inducing shed, I was able to induce ecdytic cycles in a laboratory setting and herein provide the first measurements of the metabolic effort and duration of shedding in any reptile. I integrated data on the frequency, duration, and metabolic effort of shed into an individual-based computer model of the Timber Rattlesnake to address larger questions about the selective pressures that may shape patterns of shed in snakes. I found that Timber Rattlesnakes shed infrequently (1-2 times per year) and often in close proximity to the mating season regardless of sex. However, the physiological conditions that best correlated to shed frequency differed between males (body condition) and females (reproductive condition). Each shed event required a significant metabolic (3% of the total annual energy budget) and temporal (~28 days at 25⁰C with ~50% of that including some degree of visual limitation from occluded spectacles) investment. In my computer simulations, I found that time spent in shed limited lifetime energy budgets (decreasing lifetime resource acquisition via foraging) and that the energetic effort of ecdysis may serve to limit shed frequency in low resource environments. In my observations of patterns of shed in the wild and through simulations of expected female fecundity under alternate shed frequencies, I found evidence that ecdysis may play a vital role in the reproductive biology of rattlesnakes. Ecdysis is a vital and omnipresent feature of reptilian biology. My data are the first to demonstrate that the frequency of the process is constrained in a population. I provide evidence for the role of growth and body condition, time-energy budgets, environmental conditions, and reproductive events in dictating patterns of shed. As such, patterns of shed may be population specific and serve as an indicator of the important environmental and biophysical forces which shape life histories across populations and species

Shedding in the Timber Rattlesnake: Natural Patterns, Endocrinological Underpinnings, Temporal and Energetic Effort, and Integration as a Reptilian Life History Trait

The semi-frequent replacement of the epidermis (ecdysis) is a characteristic trait of reptiles. Whereas all reptiles regularly engage in some degree of skin shedding, skin morphology in snakes necessitates the synchronous replacement of the entire epidermis and facilitates the subsequent removal of the old layer as a single sheet. To date, the ubiquitous process has garnered little attention from researchers because snakes shed with unpredictable timing and frequency and are exceedingly cryptic during ecdytic cycles; previously impeding detailed physiological or ecological investigations of the process in the clade. Because of the lack of study, ecdysis is often viewed as a maintenance function; occurring whenever change in body size necessitates the generation of a new epidermal layer. However, recent observations that skin shedding plays a role in conspecific sexual signaling in some snakes suggest that the predominate view of ecdysis as a growth function may be overly simplistic. By studying population-scale patterns of shed, I was able to describe the timing and frequency of ecdysis in a population of Timber Rattlesnakes, solving a long-standing problem in continued study of ecdysis; predicting the occurrence of shed events. Coupling my knowledge of patterns of shed timing with novel methodologies for inducing shed, I was able to induce ecdytic cycles in a laboratory setting and herein provide the first measurements of the metabolic effort and duration of shedding in any reptile. I integrated data on the frequency, duration, and metabolic effort of shed into an individual-based computer model of the Timber Rattlesnake to address larger questions about the selective pressures that may shape patterns of shed in snakes. I found that Timber Rattlesnakes shed infrequently (1-2 times per year) and often in close proximity to the mating season regardless of sex. However, the physiological conditions that best correlated to shed frequency differed between males (body condition) and females (reproductive condition). Each shed event required a significant metabolic (3% of the total annual energy budget) and temporal (~28 days at 25⁰C with ~50% of that including some degree of visual limitation from occluded spectacles) investment. In my computer simulations, I found that time spent in shed limited lifetime energy budgets (decreasing lifetime resource acquisition via foraging) and that the energetic effort of ecdysis may serve to limit shed frequency in low resource environments. In my observations of patterns of shed in the wild and through simulations of expected female fecundity under alternate shed frequencies, I found evidence that ecdysis may play a vital role in the reproductive biology of rattlesnakes. Ecdysis is a vital and omnipresent feature of reptilian biology. My data are the first to demonstrate that the frequency of the process is constrained in a population. I provide evidence for the role of growth and body condition, time-energy budgets, environmental conditions, and reproductive events in dictating patterns of shed. As such, patterns of shed may be population specific and serve as an indicator of the important environmental and biophysical forces which shape life histories across populations and species

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

Peer reviewe

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Search for Physics beyond the Standard Model in Events with Overlapping Photons and Jets

Results are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at root s = 13 TeV, and correspond to an integrated luminosity of 35.9 fb(-1). The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons.Peer reviewe

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe