Hard Ridge Research Articles

A Two-Stage Regularization Method for Variable Selection and Forecasting in High-Order Interaction Model

Forecasting models with high-order interaction has become popular in many applications since researchers gradually notice that an additive linear model is not adequate for accurate forecasting. However, the excessive number of variables with low sample size in the model poses critically challenges to predication accuracy. To enhance the forecasting accuracy and training speed simultaneously, an interpretable model is essential in knowledge recovery. To deal with ultra-high dimensionality, this paper investigates and studies a two-stage procedure to demand sparsity within high-order interaction model. In each stage, square root hard ridge (SRHR) method is applied to discover the relevant variables. The application of square root loss function facilitates the parameter tuning work. On the other hand, hard ridge penalty function is able to handle both the high multicollinearity and selection inconsistency. The real data experiments reveal the superior performances to other comparing approaches.

I Saw it Coming: My Testicular Cancer Infertility Story.

I Saw it Coming:My Testicular Cancer Infertility Story J.J. Brown It was a dull ache, but not particularly painful. That area of my body had been a little firmer than usual in the prior weeks, but I only knew something was wrong when a hard ridge popped out. It didn't go away. A few days later, Thanksgiving 2013, I was certain there was a problem. My ball was more sensitive than it should have been, and there was this persistent hard ridge. After the ridge appeared, it took a few days to check with my primary care doc, then get referred for blood work and an ultrasound, and finally get to a urologist, who told me that one ball was atrophied/damaged, and the other had cancer. Not exactly what you want to have a urologist tell you, but it wasn't a surprise by then. We scheduled surgery for the 12th of December. By that date, that hard ridge had turned into a hard object attached to my right testicle. And it was clear it was growing aggressively, having gotten much larger since I originally noticed it. It needed to go, and I was relieved when it was. A bit over [End Page 136] a month later, I started chemotherapy, just in time for my hair to fall out on my 35th birthday in early February. By April 2014, I was done with cancer treatment and set off to go rebuild my health and my professional life. A couple months later, I tried to store more sperm and received confirmation that I was totally infertile—a disappointment, but again not a surprise. I had always envisioned myself having biological kids, but by age 30 it was clear that my life was not going how I had planned. I had decided to pursue a Ph.D. and an academic career, and that had been successful but had parked me in a state of perpetual instability. In my 20s, I had worked past a lot of experiences with anxiety, but that meant I had missed a lot of the best opportunities for dating in high school and college. It also took my 20s to accept my identity as bisexual. That still remains complicated as it's turned out for me to be easier to date guys than women. My parents married when they were about 25 and I was born before they were 30. I had thought that I would be able to find a long–term relationship by the time I was 30. By that time in my life, that had still not yet happened. As the years started ticking past and it kept looking unlikely that I would have kids in the next five years, I decided by the time I turned 34 to become a sperm donor. I figured I was a good candidate for this: tall, well–educated, good–looking, family history of longevity. I reached out to my local sperm bank and tried to begin the process of becoming an anonymous donor. That plan was shot down when I disclosed that I was among the population of men who had sex with men. At the time, and I believe still currently, this population was banned by the US Food and Drug Administration from anonymous tissue donation in the USA. No blood, organ, or semen donation. It's a carry–over from the 1980s AIDS paranoia. At this writing (April 2017), this rule has been slightly relaxed to allow blood donation after one year of celibacy. So, barring that option, I started thinking about non–anonymous donation, or at least storage. I had been investigating these options for a few months already when I found the ridge on my testicle. By the time I met my urologist, I think I had already booked a storage appointment. Both he and I were prepared at that meeting to discuss implications of my surgery and chemotherapy on fertility, and he supported my action to store semen. In the end, due to the waiting time recommended between sample storage (to allow for sperm production) I only had the chance to make three "deposits" in my new bank account...

The relationship between the soft and hard ridges

Two particle correlation measurements in relativistic heavy ion collisions show a 'ridge' of correlated particle pairs not seen in proton on proton collisions. The measured two-dimentional correlation landscape resembles a mountain ridge since correlated pairs are focused into a narrow regions of relative azimuthal angle, but can extend to a long range in relative pseudorapidity. Similar ridge structures are observed in correlations of particles associated with and without a jet trigger. Explanations, with and without a jet, are challenged to explain the long range pseudorapidity behavior of correlations where causality limits the influence of transport dynamics. Glasma initial conditions as predicted by the theory of Color Glass Condensate provide a and early stage correlation that naturally extends far in rapidity. We have previously shown that the soft ridge is a consequence of particles forming from an initial Glasma phase that experience a later stage transverse flow. We extend this work to study the ridge dependence on the pt of the correlated pairs and determine the relationship between the triggered and untriggered measurements.

DECONFINEMENT, MONOPOLES AND NEW PHENOMENA IN HEAVY ION COLLISIONS

We discuss various manifestations of the "magnetic scenario" for the quark-gluon plasma viewed as a mixture of two plasmas, of electrically (quark and gluons) as well as magnetically charged quasiparticles. Near the deconfinement phase transition, T ≈ Tc very small density of free quarks should lead to negligible screening of electric field while magnetic screening remains strong. The consequence of this should be existence of a "corona" of the QGP, in a way similar to that of the Sun, in which electric fields influence propagation of perturbations and even form metastable flux tubes. The natural tool for its description is (dual) magnetohydrodynamics: among observable consequences is splitting of sound into two modes, with larger and smaller velocity. The latter can be zero, hinting for formation of pressure-stabilized flux tubes. Remarkably, recent experimental discoveries at RHIC show effects similar to expected for "corona structures". In dihadron correlation function with large-pt trigger there are a "cone" and a "hard ridge", while the so called "soft ridge" is a similar structure seen without hard trigger. They seem to be remnants of flux tubes, which – contrary to naive expectations – seem to break less often in near-Tc matter than do confining strings in vacuum.

Soft contribution to the hard ridge in relativistic nuclear collisions

Nuclear collisions exhibit near side long-range rapidity correlations not present in proton–proton collisions. Because the correlation structure is wide in relative pseudorapidity and narrow in relative azimuthal angle, it is known as the ridge. Similar ridge structures are observed in correlations of particles associated with a jet trigger (the hard ridge) as well as correlations without a trigger (the soft ridge). Earlier we argued that the soft ridge arises when particles formed in an early Glasma stage later manifest transverse flow. We extend this study to address new soft ridge measurements. We then determine the contribution of flow to the hard ridge.

Erratum: Fate of the initial state perturbations in heavy ion collisions [Phys. Rev. C80, 054908 (2009)

Heavy ion collisions at RHIC are well described by the (nearly ideal) hydrodynamics. In the present paper we study propagation of perturbations induced by moving charges (jets) on top of the expanding fireball, using hydrodynamics and (dual) magnetohydrodynamics. Two experimentally observed structures, called a "cone" and a "hard ridge", have been discovered in dihadron correlation function with large-$p_t$ trigger, while "soft ridge" is a similar structure seen without hard trigger. All three can be viewed as traces left by a moving charge in matter, on top of overall expansion. A puzzle is why those perturbations are apparently rather well preserved at the time of the fireball freezeout. We study two possible solutions to it: (i) a "wave-splitting" acoustic option and (ii) a "metastable electric flux tubes". In the first case we show that rapidly variable speed of sound under certain conditions leads to secondary sound waves, which are at freezeout time closer to the original location and have larger intensities than the first wave. In the latter case we rely on (dual) magnetohydrodynamics, which also predicts two cones or cylinders of the waves. We also briefly discuss metastable electric flux tubes in the near-$T_c$ phase and their relation to clustering data.

Fate of the initial state perturbations in heavy ion collisions

Heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) are well described by the (nearly ideal) hydrodynamics. In the present paper, we study the propagation of perturbations induced by moving charges (jets) on top of the expanding fireball, using hydrodynamics and (dual) magnetohydrodynamics. Two experimentally observed structures, called a ``cone'' and a ``hard ridge'', have been discovered in a dihadron correlation function with a large-${p}_{t}$ trigger, while a ``soft ridge'' is a similar structure seen without a hard trigger. All three can be viewed as traces left by a moving charge in matter, on top of overall expansion. A puzzle is why those perturbations are apparently rather well preserved at the time of the fireball freeze-out. We study two possible solutions: (A) a ``wave-splitting'' acoustic option and (B) a ``metastable electric flux tube'' option. In the first case, we show that rapidly variable speed of sound under certain conditions leads to secondary sound waves, which are at freeze-out time closer to the original location and have larger intensities than the first wave. In the latter case, we rely on (dual) magnetohydrodynamics, which also predicts two cones or cylinders of the waves. We also briefly discuss metastable electric flux tubes in the near-${T}_{c}$ phase and their relation to clustering data.

Two Ridges, One Explanation

We attribute the phenomenon known as “the ridge” to long range initial state correlations from Color Glass Condensate flux tubes and later stage radial flow. We show that this description can explain the amplitude and azimuthal width of the soft ridge and nearly explain that of the hard ridge, suggesting that the two are essentially the same phenomenon.

First report on Rhabdocoela (Rhabditophora) from deep parts of Skagerrak, with the description of four new species

In this contribution we report on 13 species of Rhabdocoela, found during a marine inventory of Skagerrak by the Swedish Taxonomy Initiative. Four new species are described, two of which are Kalyptorhynchia (Gnathorhychidae and Polycystididae) and two belong to Dalytyphloplanoida (Solenopharyngidae). Uncinorhynchus vorago sp. nov., (Gnathorhynchidae) has a triangular stylet consisting of a double-folded plate, which proximally forms a tube, but without a distal, needle-shaped tip. Austrorhynchus artoisi sp. nov. (Polycystididae), has two prostate stylets. Prostate stylet type II consists of a distal tube and a short proximal funnel, which has a stirrup-shaped ornament, whereas the stylet type III shows an unpronounced foot and style connected to each other by a narrow clasp and a comb-bearing plate. The foot and plate are connected to a thread-like flagellum. Lenopharynx bathos sp. nov. (Solenopharyngidae) resembles Lenopharynx tubatus Schockaert & Martens, 1985, but differs in the detailed structure of the stylet and by the lack of colouration and eyes. Proceropharynx profundum sp. nov. has a unique combination of small spines and hard ridges on the cirrus. Additional data are given for the remaining nine species, three of which are new for the Swedish fauna. Espegrendia norvegica Westblad, 1954 (Solenopharyngidae) is redescribed. For the sake of completeness, two more species are mentioned. One is identified as a new species of Acrumena Brunet, but lack of material prevents its formal description. The second one is probably a representative of the taxon Ceratopera Den Hartog, but cannot be identified with certainty because of the poor quality of the preserved material. This contribution is one of very few reports on Rhabdocoela collected from a depth exceeding 100 m and some preliminary biogeographical remarks are therefore given.

Functional and Corrective Claw Trimming

Foot care and claw trimming require proper systems for restraint, sharp knives and trimming equipment, and an understanding of the biomechanics of weight bearing and hoof overgrowth in cattle. The objective of functional claw trimming is to correct hoof overgrowth, thereby re-establishing appropriate weight bearing within and between the claws of each foot. Traditional trimming methods fail to achieve these objectives. Corrective trimming procedures are applied to horn lesions affecting the claw capsule. Primary objectives of corrective trimming are to adjust weight bearing to provide rest for diseased claws and to remove loose horn and hard ridges that may cause further injury to the corium. The application of a foot block to the healthy claw is a valuable aid in foot care when corrective trimming alone is insufficient to provide needed relief from weight bearing. Finally, the use of topical treatments under a bandage is controversial. It is recommended that caustic treatments be avoided and that the use of a bandage be limited to conditions requiring hemostasis or when operators are committed to their removal within a period of 2 to 5 days depending on the level of environmental contamination.