Deep negative volume segmentation

Clinical examination of three-dimensional image data of compound anatomical objects, such as complex joints, remains a tedious process, demanding the time and the expertise of physicians. For instance, automation of the segmentation task of the TMJ (temporomandibular joint) has been hindered by its compound three-dimensional shape, multiple overlaid textures, an abundance of surrounding irregularities in the skull, and a virtually omnidirectional range of the jaw’s motion—all of which extend the manual annotation process to more than an hour per patient. To address the challenge, we invent a new workflow for the 3D segmentation task: namely, we propose to segment empty spaces between all the tissues surrounding the object—the so-called negative volume segmentation. Our approach is an end-to-end pipeline that comprises a V-Net for bone segmentation, a 3D volume construction by inflation of the reconstructed bone head in all directions along the normal vector to its mesh faces. Eventually confined within the skull bones, the inflated surface occupies the entire “negative” space in the joint, effectively providing a geometrical/topological metric of the joint’s health. We validate the idea on the CT scans in a 50-patient dataset, annotated by experts in maxillofacial medicine, quantitatively compare the asymmetry given the left and the right negative volumes, and automate the entire framework for clinical adoption.

The disk partition function in string theory

We investigate the disk partition function for the open string. This is a subtle problem because of the presence of a residual gauge group PSL(2, ℝ) on the worldsheet even after fixing the conformal gauge. It naively has infinite volume and leads to a vanishing answer. We use different methods that all demonstrate that PSL(2, ℝ) effectively behaves like a group with finite negative volume in the path integral, which leads to a simple prescription for the computation of the disk partition function. We apply our findings to give a simple rederivation of the D-brane tensions.

Improving on the Adrogué-Madias Formula

The Adrogué-Madias (A-M) formula is correct as written, but technically it only works when adding one liter of an intravenous (IV) fluid. For all other volumes, the A-M algorithm gives an approximate answer, one that diverges further from the truth as the IV volume is increased. If one liter of an IV fluid is calculated to change the serum sodium by some amount, then it was long assumed that giving a fraction of the liter would change the serum sodium by a proportional amount. We challenged that assumption and now prove that the A-M change in [sodium] is not scalable in a linear way. Rather, the delta [Na] needs to be scaled in a way that accounts for the actual volume of IV fluid being given. This is accomplished by our improved version of the A-M formula in a mathematically rigorous way. Our equation accepts any IV fluid volume, eliminates the illogical infinities, and, most importantly, incorporates the scaling step so that it cannot be forgotten. However, the non-linear scaling makes it harder to obtain a desired delta [Na]. Therefore, we reversed the equation so that clinicians can enter the desired delta [Na], keeping the rate of sodium correction safe, and then get an answer in terms of the volume of IV fluid to infuse. The improved equation can also unify the A-M formula with the corollary A-M loss equation wherein one liter of urine is lost. The method is to treat loss as a negative volume. Since the new equation is just as straightforward as the original formula, we believe that the improved form of A-M is ready for immediate use, alongside frequent [sodium] monitoring.

Empirical analysis on the illicit trade of cigarettes in Vietnam

BackgroundThis paper examined how a higher tax on tobacco would affect illicit trade in Vietnam.Methodology and dataThis paper used the gap method to estimate the gap between cigarette domestically tax-paid sales and domestic consumption. Data were from the tax-paid sales by the Vietnam Steering Committee on Smoking and Health (VINACOSH), the Vietnam Tobacco Association, the General Tax Department, as well as two rounds of the Global Adult Tobacco Survey in 2010 and 2015.Key resultsThe results indicated that Vietnam had a negative volume of illicit trade, either a result of under-reporting of tobacco use or due to net smuggling of tax-paid cigarettes out of the country. Furthermore, the trend showed an increased negative volume over time, which indicated that increases in tobacco taxes in the interleading years did not result in an increase in illicit trade in tobaccos in Vietnam.ConclusionsVietnam’s low prices on domestic cigarettes created favourable conditions for cigarette smugglers and provided easy access to illicit cigarettes for the Vietnamese people, but the absence of a relationship between tax changes and smuggling suggested that potential increases in the excise tax should not be discouraged by the threat of an increase in illicit trade. The government should increase taxes on cigarettes to raise domestic cigarette prices and take strong policy measures to create a more transparent social environment, therefore effectively reducing the prevalence of illicit cigarettes in Vietnam.

Revealing unfolding steps and volume changes of human telomeric i-motif DNA

The i-motif structure of the human telomeric DNA was destabilized by pressure and unfolded with a negative volume change.

Geology of Chernogorskoe gem-quality skapolite deposit (Central Pamirs, Tajikistan)

The Montenegrin jewel scapolite deposit, which relates to a new genetic type, is characterized. It is located in the Central Pamirs (Tajikistan) and is localized in the sarydzhilginsk formation of the muzkol series (PR1). The enclosing rocks are metamorphosed basite-ultrabasic formations of the kukurt complex, among which harzburgites were first discovered. Jewel scapolite mineralization contains albitite lenses. They were formed by the metasomatic replacement of nepheline syenites. The reaction occurred with a negative volume effect with a decrease in the volume of solid phases 14%, which caused the appearance of voids. Albitite bodies form a lenticular nesting structure. They have cross-cutting contacts. They are accommodated by amphibolites, which metasomatically replace melanocratic gabbroids and partially altered harzburgites. Jewelry scapolite is localized in 28 albitite lenses, the walls of the voids of which are inlaid with columnar purple scapolite. The sequence of processes at the field corresponds to the following scheme: formation of melanocratic gabbroids with small bodies of nepheline syenites metasomatic development in the first amphibolites, and in the second albitites with voids growth on the walls of the hollows of the hollow scapolite crystallization in the voids of the jewelry scapolite.