Dark Space Research Articles

Into Darkness: Affect and Dark Space in Holocaust Exhibitions

Abstract Since 1990, many Holocaust exhibitions have featured dark spaces. This article considers the development of these dark spaces and their display function at two institutions: the Holocaust Exhibition at the Imperial War Museum, London and the United States Holocaust Memorial Museum, Washington DC. By examining shifts in exhibition lighting, a correlation can be found between brighter displays addressing the broad sociopolitical context of Nazism and darker displays focusing more on individual experiences of the death camps. Drawing from phenomenology and museology, this article argues that museums utilize darkness to lead visitors to particular affective experiences and to provoke inquiry into the meanings of the Holocaust.

Probing light dark matter via evaporation from the Sun

Dark matter particles can be captured by the sun with rates that depend on the dark matter mass and the DM-nucleon cross section. However, for masses below $\sim 3.3$ GeV, the captured dark matter particles evaporate, leading to an equilibrium where the rate of captured particles is equal to the rate of evaporating ones. Unlike dark matter particles from the halo, the evaporating dark matter particles have velocities that are not limited to values below the escape velocity of the galaxy. Despite the fact that high velocities are exponentially suppressed, I demonstrate here that current underground detectors have the possibility to probe/constrain low dark matter parameter space by (not)-observing the high energy tail of the evaporating dark matter particles from the sun. I also show that the functional form of the differential rate of counts with respect to the recoil energy in earth based detectors can identify precisely the mass and the cross section of the dark matter particle in this case.

Dynamical decomposition theorems of homeomorphisms with zero-dimensional sets of periodic points

In this note, we study some dynamical decomposition theorems of spaces related to given homeomorphisms. First, we prove that if f:X→X is a homeomorphism of an n-dimensional separable metric space X with zero-dimensional set of periodic points, then X can be decomposed into a zero-dimensional bright space of f except n times and an (n−1)-dimensional dark space of f except n times, and also by use of dark spaces, we prove some decomposition theorems of X related to dimension theory and dynamical systems. Finally, we study dynamical decompositions of continuum-wise expansive homeomorphisms.

Critical Punishment Memorialization in Canada

Recent criminological scholarship on penal history museums has shown how sites of popular culture tend to silence the voices of prisoners and present them in ways that legitimate the deprivation of their liberty. While representations that reinforce the penal status quo are observable at most Canadian penal history sites, there are outliers that situate imprisonment as a form of oppression, and account for prisoners’ struggles and resistance. Drawing on three case studies from a 5-year qualitative research project on Canadian lock-up, jail, prison and penitentiary museums, we discuss what critical punishment memorialization looks like in a context of penal intensification in Canada. We show how such critical representations depend on the historical contextualization of penality as a manifestation of colonialism and/or the incorporation of prisoners’ voices and standpoint. We argue that the critical representations and narratives at these museum sites open up possibilities for the social distance between penal spectators and the incarcerated to be diminished by bringing humanizing prisoner narratives into focus in an otherwise dark tourist space.

Making the most of the relic density for dark matter searches at the LHC 14 TeV Run

As the LHC continues to search for new weakly interacting particles, it is important to remember that the search is strongly motivated by the existence of dark matter. In view of a possible positive signal, it is essential to ask whether the newly discovered weakly interacting particle can be be assigned the label “dark matter”. Within a given set of simplified models and modest working assumptions, we reinterpret the relic abundance bound as a relic abundance range, and compare the parameter space yielding the correct relic abundance with projections of the Run II exclusion regions. Assuming that dark matter is within the reach of the LHC, we also make the comparison with the potential 5σ discovery regions. Reversing the logic, relic density calculations can be used to optimize dark matter searches by motivating choices of parameters where the LHC can probe most deeply into the dark matter parameter space. In the event that DM is seen outside of the region giving the correct relic abundance, we will learn that either thermal relic DM is ruled out in that model, or the DM-quark coupling is suppressed relative to the DM coupling strength to other SM particles.

Selected 10 Bilingual Poems: luck of the draw; widowed; the old woman; love and breath; Edeilweiss áo dài; colonization of the Vagina; the dark space under the bed; my first April thirtieth; reversed sub-thoughts; seeing Gram

Selected 10 Bilingual Poems: luck of the draw; widowed; the old woman; love and breath; Edeilweiss áo dài; colonization of the Vagina; the dark space under the bed; my first April thirtieth; reversed sub-thoughts; seeing Gram

Assessing Performance of Glow-in-the-Dark Concrete

The objective of this research was to develop a soy-based luminescent sealant for use on concrete surfaces. The luminescent sealant was a mixture of soy methyl ester polystyrene and strontium aluminate, a phosphorescent powder that slowly luminesces after being excited by light. A test procedure was developed to quantify the magnitude and duration of the luminance of the coated concrete surface; quantifying the luminance was key in evaluating the performance of the luminescent sealant. The luminescent sealant was excited in a consistent manner with a xenon lighting system that simulated sunlight, a photometer (light-measuring instrument) that measured the luminance of the excited concrete surface, and a housing unit that prevented extraneous light from the surroundings from influencing the test results. Results of the tests indicated that the luminescent surface emitted light (i.e., glowed) for approximately 24 h in a dark space after it was excited. Larger particles of strontium aluminate were found to luminesce for a longer time than did smaller particles. The excited sealant's luminance was independent of the amount of time it was exposed to light coming from the xenon lighting system.

Bringing light into the dark triplet space of molecular systems.

A molecule or a molecular system always consists of excited states of different spin multiplicities. With conventional optical excitations, only the (bright) states with the same spin multiplicity of the ground state could be directly reached. How to reveal the dynamics of excited (dark) states remains the grand challenge in the topical fields of photochemistry, photophysics, and photobiology. For a singlet-triplet coupled molecular system, the (bright) singlet dynamics can be routinely examined by conventional femtosecond pump-probe spectroscopy. However, owing to the involvement of intrinsically fast decay channels such as intramolecular vibrational redistribution and internal conversion, it is very difficult, if not impossible, to single out the (dark) triplet dynamics. Herein, we develop a novel strategy that uses an ultrafast broadband white-light continuum as a excitation light source to enhance the probability of intersystem crossing, thus facilitating the population flow from the singlet space to the triplet space. With a set of femtosecond time-reversed pump-probe experiments, we report on a proof-of-concept molecular system (i.e., the malachite green molecule) that the pure triplet dynamics can be mapped out in real time through monitoring the modulated emission that occurs solely in the triplet space. Significant differences in excited-state dynamics between the singlet and triplet spaces have been observed. This newly developed approach may provide a useful tool for examining the elusive dark-state dynamics of molecular systems and also for exploring the mechanisms underlying molecular luminescence/photonics and solar light harvesting.

Searches for low mass CP-odd Higgs and dark photons at BaBar

We report recent searches for new physics by the BaBar experiment in two sectors: the search for dark photons and the search for CP-odd light Higgs A0. We do not observe significant signals. We set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of 10−4 – 10−3 for dark photon masses in the range 0.02 – 10.2 GeV/c2. We further constrain the range of the dark photon parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon. We set 90% confidence-level upper limits on the product branching fraction B(ϒ(1S)→γA0)⋅B(A0→gg or ss¯) ranging from 10−6 to 10−2 for A0 masses in the range 0.5 to 9.0 GeV/c2.

Realization of DC atmospheric pressure glow discharge without external airflow

A new needle-to-cylinder electrode structure with small gap (1.5 mm) was designed to realize the stable gas discharge in ambient air. The stable corona discharge and the stable glow discharge were realized without external airflow, which was proved by the discharge waveform stored in the oscilloscope, the discharge pictures recorded by the digital camera and the voltage–current plot. The image of the glow discharge showed that there was a negative glow region, Faraday dark space, a positive column region and an anode spot. Also the experiment and the COMSOL simulation showed that the needle with a diameter of 56.4 μm can realize the glow discharge while the needle with a diameter of 626 μm can not. The reasons for the realization of the glow discharge by the small gap between the needle and the cylinder were analyzed. It also shows that the glow discharge is easily realized with the black spot on the cylinder surface and a proper ballast resistor value (larger than 2 MΩ and less than 30 MΩ). The needle-to-cylinder electrode structure is easy to fabricate by MEMS technology, which can be used in portable analytical instruments.

“The Most Notorious Sucker-Trap in the Western Hemisphere”:The Tijuana Story(Leslie Kardos, 1957) and Mythologies of Tijuana in American Cinema

The histories of Tijuana and Hollywood have long been deeply intertwined, leading critics to argue that American cinema was instrumental in constructing the city's reputation as a dark, seedy and amoral space. However, the 1957 filmThe Tijuana Storypresents a clear contradiction between the way in which it is marketed to evoke the “black legend” of Tijuana and its socially conscious content, tracing the real life story of a Tijuanan journalist who was murdered for taking a stand against crime and corruption. Close analysis ofThe Tijuana Story's paradoxical representation of the city provides a more detailed understanding of Hollywood's relationship with Tijuana and offers a way of discussing the city without reducing it to any one singular mythology. As part of a larger body of films that use images of Mexico to explore left-wing and liberal politics,The Tijuana Storyprovides further evidence of the persistent connection between Mexico and social revolution in American cinema.

Cycling through Dark Space: Apprehending Landscape Otherwise

By investigating the experience of night-cycling, this paper redresses the overwhelming focus in mobility studies on the apprehension of landscape by daylight. Drawing on Matt’s cycling diary of his regular night rides through rural Bedfordshire, we explore the distinctive ways in which dark landscape is experienced. We discuss various effects: the shaping of perception by the beam of the head torch; an ongoing attunement to differing levels of light and dark; the affordances of the cycle and other equipment; enhanced awareness of the vital rhythms of landscape; and imaginaries stimulated by passage through darkness. We, thereby, aim to contribute to revaluing darkness.

Inert doublet dark matter with an additional scalar singlet and 125 GeV Higgs boson

In this work we consider a model for particle dark matter where an extra inert Higgs doublet and an additional scalar singlet is added to the Standard Model (SM) Lagrangian. The dark matter candidate is obtained from only the inert doublet. The stability of this one component dark matter is ensured by imposing a $Z_2$ symmetry on this additional inert doublet. The additional singlet scalar has a vacuum expectation value (VEV) and mixes with the Standard Model Higgs doublet resulting in two CP even scalars $h_1$ and $h_2$. We treat one of these scalars, $h_1$, to be consistent with the SM Higgs like boson of mass around 125 GeV reported by the LHC experiment. These two CP even scalars affect the annihilation cross-section of this inert doublet dark matter resulting in a larger dark matter mass region that satisfies the observed relic density. We also investigate the $h_1 \rightarrow \gamma\gamma$ and $h_1 \rightarrow \gamma Z$ processes and compared these with LHC results. This is also used to constrain the dark matter parameter space in the present model. We find that the dark matter candidate in the mass region $\frac {m_1} {2} < m_H < m_W$ GeV ($m_1 = 125$ GeV, mass of $h_1$) satisfies the recent bound from LUX direct detection experiment.

Schwarzschild black hole in dark energy background

In this paper we present an exact solution of Einstein's field equations describing the Schwarzschild black hole in dark energy background. It is also regarded as an embedded solution that the Schwarzschild black hole is embedded into the dark energy space producing Schwarzschild-dark energy black hole. It is found that the space-time geometry of Schwarzschild-dark energy solution is non-vacuum Petrov type $D$ in the classification of space-times. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor of the Schwarzschild-dark energy solution. We also find that the energy-momentum tensor of the Schwarzschild-dark energy solution violates the strong energy condition due to the negative pressure leading to a repulsive gravitational force of the matter field in the space-time. It is shown that the time-like vector field for an observer in the Schwarzschild-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity and the area of the horizons for the Schwarzschild-dark energy black hole.

Characterization of argon direct-current glow discharge with a longitudinal electric field applied at ambient air.

A direct-current-driven plasma jet is developed by applying a longitudinal electric field on the flowing argon at ambient air. This plasma shows a torch shape with its cross-section increased from the anode to the cathode. Comparison with its counterparts indicates that the gas flow plays a key role in variation of the plasma structure and contributes much to enlarging the plasma volume. It is also found that the circular hollow metal base promotes generation of plasma with a high-power volume density in a limited space. The optical emission spectroscopy (OES) diagnosis indicates that the plasma comprises many reactive species, such as OH, O, excited N2, and Ar metastables. Examination of the rotational and vibrational temperature indicates that the plasma is under nonequilibrium condition and the excited species OH(A 2Σ+), O(5P), and N2(C 3Πu) are partly generated by energy transfer from argon metastables. The spatially resolved OES of plasma reveals that the negative glow, Faraday dark space, and positive column are distributed across the gas gap. The absence of the anode glow is attributed to the fact that many electrons in the vicinity of the anode follow ions into the positive column due to the ambipolar diffusion in the flowing gas.

Lepton Portal dark matter

We study a class of simplified dark matter models in which dark matter couples directly with a mediator and a charged lepton. This class of Lepton Portal dark matter models has very rich phenomenology: it has loop generated dark matter electromagnetic moments that generate a direct detection signal; it contributes to indirect detection in the cosmic positron flux via dark matter annihilation; it provides a signature of the same-flavor, opposite-sign dilepton plus missing transverse energy at colliders. We determine the current experimental constraints on the model parameter space for Dirac fermion, Majorana fermion and complex scalar dark matter cases of the Lepton Portal framework. We also perform a collider study for the 14 TeV LHC reach with 100 inverse femtobarns for dark matter parameter space. For the complex scalar dark matter case, the LHC provides a very stringent constraint and its reach can be interpreted as corresponding to a limit as strong as two tenths of a zeptobarn on the dark matter-nucleon scattering cross section for dark matter masses up to 500 GeV. We also demonstrate that one can improve the current collider searches by using a Breit-Wigner like formula to fit the dilepton MT2 tail of the dominant diboson background.

Characteristics of eyes with inner retinal cleavage.

Inner retinal cleavage can be misdiagnosed as a glaucomatous retinal nerve fiber layer (RNFL) defect. This study was performed to characterize eyes with inner retinal cleavage. Inner retinal cleavage is defined as the appearance of a dark spindle-shaped space between the nerve fibers. Patients who presented at our institution with inner retinal cleavage were enrolled in the study. All participants were evaluated by fundus examination, visual field testing with standard automated perimetry, and optical coherence tomography (OCT) imaging. A total of 15 eyes of 11 subjects with inner retinal cleavage were included in the study. The median age of the subjects was 57years (age range, 30-67years). In each case, inner retinal cleavage was located adjacent to retinal blood vessels. Tissue bridging the cleavage area was observed in ten eyes. Six eyes had epiretinal membranes (ERMs), two eyes had glaucoma, and one eye had ERM in addition to glaucoma. Six eyes with inner retinal cleavage without combined ocular abnormalities had highly myopic refractive error (-6.50 to -8.50 diopters). Cross-sectional OCT images of the areas of inner retinal cleavage demonstrated defects with irregular margins and empty spaces in the inner layers of the retina. During the follow-up period, no eye showed changes in inner retinal layer cleavage or visual field sensitivity. Inner retinal cleavage was found in eyes with high myopia or ERMs. Inner retinal cleavage was associated with structural changes distinct from those associated with glaucomatous RNFL defects.

Clinical characteristics of 23 cases in two months old of neonatal lingual thyroglossal duct cysts

Objective To analyse the clinical characteristics of infants in two months old of lingual thyroglossal duct cysts (LTGDC) and raise the levels of diagnosis and treatment. Methods A comparative analysis was made between the clinical data of 23 cases in two months old of LTGDC and those of 20 cases in one to seven years old of cervical thyroglossal duct cysts (TGDC) (control group). Results The clinical manifestation appeared obviously differences between LTGDC and TGDC. The main performance of LTGDC was laryngeal stridor, and 74% of them went to emergency department because of dyspnea. They would be misdiagnosed as congenital laryngomalacia or laryngomalacia with pneumonia. The lesion located in the posterosuperior of lingual bone and behind the root of tongue, which was easy to lead to throat obstruction because it extruded laryngeal cavity. Electronic laryngoscopy was the first choice, it helped to identify laryngomalacia, epiglottis cyst and hemangioma. Laryngeal CT or MRI was very important to diagnose LTGDC which was quasi-circular low density shadow with clear boundary, or not extruded to laryngeal cavity, or show lesion range and surrounding structures avoiding misdiagnosis. As treatment depended surgery which was self-retaining laryngoscope, it was minimally invasive and without scar. Cervical anterior mass in the midline was the first symptoms in all 20 cases of TGDC. The neck ultrasound examination was the first selection, and the lesion showed fluid dark space with clear boundary, it should take the neck percutaneous surgical operation. Conclusion The clinical manifestation of infants in two months old of LTGDC appears obviously different from TGDC. LTGDC is a common cause of laryngeal stridor with breathing difficulties. It will be misdiagnosed as congenital laryngomalacia and lead to asphyxia or death easily. Key words: Lingual thyroglossal duct cyst; Dyspnea; Infants

A source of a wide-aperture gas-discharge plasma flow

The described generator produces a wide-aperture flow of charged plasma particles (electrons, positive and negative ions) with a cross-sectional diameter of at least 120 cm, which propagates to a distance of 50 cm or more (depending on the operating mode and the geometric dimensions of the vacuum chamber). The uniform distribution of charged particles in the cross section of the plasma flow is at least 98%. The discharge current reaches 1 A or more at an accelerating voltage of 0.3–6 kV. The energy of particles in the plasma flow under such conditions was 10–6000 eV at current densities of up to 10 mA/cm2. The generator structure contains coaxially positioned meshes of the anode grid and the cathode grid. The latter closes the cavity inside the cathode volume at a depth of 3–5 mean free paths of electrons in the gas-discharge plasma flow. The cathode is manufactured so that the cavity diameter exceeds the diameter of the through cavity in the cathode insulation, the latter being determined by the size of the plasma-flow cross section. The distance between the grid anode and the cathode grid is equal to the Aston dark space of a glow discharge, thus permitting the cathode lifetime to be increased to 3 years. It is shown that the duration of the cathode continuous operation is determined by the chosen values of its cavity depth and accelerating voltage.

'An Idealistic Utopian Thought': Paul McCarthy and the Spaces of Transmission

In 1974, visitors to the Newspace Gallery on Melrose Avenue experienced a studio tour very different from the one tourists might have encountered just a few blocks west at Paramount Studios.1 Viewers passed through a dimly lit room into a dark space illuminated by two black-and-white television monitors on tall stands. The video shown on the monitors was Paul McCarthy's Meat Cake #5, in which the artist, wearing a black dress and alternating wigs, can be seen covering himself with combinations of margarine, minced meat, mayonnaise, and ketchup.2 A black plastic curtain hanging over the rear wall of the gallery concealed a door leading to an adjacent room. The performance on the monitors was, in fact, taking place in that room, and viewers who realised this could pass back-and-forth between the two spaces. In contrast to the first room, the back room-turned-soundstage was brightly lit and redolent with the smells of ketchup, mayonnaise, and margarine, condiments that were quickly becoming mainstays of McCarthy's visceral performances.3