Search for Oscillation of the Electron-Capture Decay Probability of 142^{142}Pm

We have searched for time modulation of the electron capture decay probability of $^{142}$Pm in an attempt to confirm a recent claim from a group at the Gesellschaft f\"{u}r Schwerionenforschung (GSI). We produced $^{142}$Pm via the $^{124}$Sn($^{23}$Na, 5n)$^{142}$Pm reaction at the Berkeley 88-Inch Cyclotron with a bombardment time short compared to the reported modulation period. Isotope selection by the Berkeley Gas-filled Separator is followed by implantation and a long period of monitoring the $^{142}$Nd K$_{\alpha}$ x-rays from the daughter. The decay time spectrum of the x-rays is well-described by a simple exponential and the measured half-life of 40.68(53) seconds is consistent with the accepted value. We observed no oscillatory modulation at the proposed frequency at a level 31 times smaller than that reported by Litvinov {\it et al.} (Phys. Lett. B 664 (2008) 162; arXiv:0801.2079 [nucl-ex]). A literature search for previous experiments that might have been sensitive to the reported modulation uncovered another example in $^{142}$Eu electron-capture decay. A reanalysis of the published data shows no oscillatory behavior.Comment: 12 pages (double-spaced), 6 figure

A Tobamovirus Genome That Contains an Internal Ribosome Entry Site Functionalin Vitro

AbstractMost eukaryotic mRNAs are translated by a “scanning ribosome” mechanism. We have found that unlike the type member of the genusTobamovirus,translation of the 3′-proximal coat protein (CP) gene of a crucifer infecting tobamovirus (crTMV) (Dorokhovet al.,1993; 1994) occurredin vitroby an internal ribosome entry mechanism. Three types of synthetic dicistronic RNA transcripts were constructed and translatedin vitro:(i) “MP-CP-3′NTR” transcripts contained movement protein (MP) gene, CP gene and the 3′-nontranslated region of crTMV RNA. These constructs were structurally equivalent to dicistronic subgenomic RNAs produced by tobamovirusesin vivo.(ii) “ΔNPT-CP” transcripts contained partially truncated neomycin phosphotransferase I gene and CP gene. (iii) “CP-GUS” transcripts contained the first CP gene and the gene ofEscherichia coliβ-glucuronidase (GUS) at the 3′-proximal position. The results indicated that the 148-nt region upstream of the CP gene of crTMV RNA contained an internal ribosome entry site (IRESCP) promoting internal initiation of translationin vitro.Dicistronic IRESCP, containing chimeric mRNAs with the 5′-terminal stem–loop structure preventing translation of the first gene (MP, ΔNPT, or CP), expressed the CP or GUS genes despite their 3′-proximal localization. The capacity of crTMV IRESCPfor mediating internal translation distinguishes this CP tobamovirus from the well-known-type member of the genus, TMV UI. The equivalent 148-nt sequence from TMV RNA was incapable of mediating internal translation. Two mutants were used to study structural elements of IRESCP. It was concluded that integrity of IRESCPwas essential for internal initiation. The crTMV provides a new example of internal initiation of translation, which is markedly distinct from IRESs shown for picornaviruses and other viral and eukaryotic mRNAs

Possible Z2 phase and spin-charge separation in electron doped cuprate superconductors

The SU(2) slave-boson mean-field theory for the tt'J model is analyzed. The role of next-nearest-neighbor hopping t' on the phase-diagram is studied. We find a pseudogap phase in hole-doped materials (where t'<0). The pseudo-gap phase is a U(1) spin liquid (the staggered-flux phase) with a U(1) gauge interaction and no fractionalization. This agrees with experiments on hole doped samples. The same calculation also indicates that a positive t' favors a Z2 state with true spin-charge separation. The Z2 state that exists when t' > 0.5J can be a candidate for the pseudo-gap phase of electron-doped cuprates (if such a phase exists). The experimental situation in electron-doped materials is also addressed.Comment: 6 pages, 2 figures, RevTeX4. Homepage http://dao.mit.edu/~wen

Новый способ открытой репозиции и удержания костных отломков с использованием пластиковых хомутов-стяжек

Background. The quality of fractures reposition in open osteosynthesis is one of the important factors determining the outcome of treatment. Often, the reposition and fixation of bone fragments is not an easy task. The authors propose a method of reposition and temporary fixation of fragments using plastic ty-raps used in electrical work. The aim of the study is to demonstrate the possibilities of new method of intraoperative reposition and fixation of bone fragments using plastic ty-raps. Materials and Methods. Ty-raps were sterilized before the surgery in the modes intended for the preparation of polymer products. After the fragments were dissected, their reposition and fixation are carried out with the help of clamps and bone clamps. At this stage, there is a need for the use of ty-raps, since the bone clamps prevent the plate from laying on the bone. To do this, 3-4 plastic ty-raps were applied to the areas of bone free from bone clamps in the area of the fragments contact. In those places where an intact periosteum and muscles are attached to the fragment, narrow transverse channels in soft tissues are formed with the instrument to wrap the bone with a ty-rap. Then the free end of the ty-rap is passed through its lock and tightened as much as possible. After tightening all the ty-raps, the bone clamps are removed. The applied ty-raps reliably keep the bone fragments from any displacement, even when the segment rotates. A bone plate is placed on the bone surface with tightened ty-raps. Then the plate fixed to the bone with screws. The plate should be placed on the bone without strong pressing, which allows you to remove the ty-raps from under the plate at any stage of osteosynthesis. The ty-raps are removed by cutting them with a scalpel or snacking with wire cutter, then the plate is fixed to the bone with the remaining screws. Conclusion. Ty-raps have many positive properties: they are affordable, cheap, do not lose their mechanical properties after sterilization, allow you to securely hold bone fragments during reposition, X-ray negative. The method has demonstrated convenience and reliability.Актуальность. Качество репозиции отломков при открытом остеосинтезе является одним из важных факторов, определяющих исход лечения. Нередко репозиция и удержание костных отломков представляют собой непростую задачу. Авторами предложен способ репозиции и временного удержания отломков с использованием пластиковых хомутов-стяжек, используемых при электромонтажных работах. Цель продемонстрировать возможности нового способа интраоперационной репозиции и удержания костных отломков при помощи пластиковых хомутов-стяжек. Материал и методы. Хомуты-стяжки перед операцией подвергают стерилизации в режимах, предназначенных для подготовки полимерных изделий. После выделения отломков осуществляют их репозицию и удержание с помощью зажимов и костодержателей. На этом этапе операции возникает потребность в применении хомутов-стяжек, так как костодержатели препятствуют укладке пластины на кость. Для этого на свободные от костодержателей участки кости в области стыковки отломков накладывают 34 пластиковых хомута-стяжки. В тех местах, где к отломку прикрепляются неповрежденная надкостница и мышцы, инструментом формируют узкие поперечные каналы в мягких тканях для обхватывания кости хомутом. Затем свободный конец хомута проводят через его замок и максимально затягивают. После затягивания всех хомутов костодержатели снимают. Наложенные хомуты надежно удерживают костные фрагменты от каких-либо смещений даже при ротации сегмента. Поверх кости с затянутыми хомутами-стяжками укладывают накостный фиксатор. Затем фиксируют пластину к кости винтами. Следует укладывать пластину на кость без сильного прижатия, что позволяет удалять хомуты-стяжки из-под пластины на любом этапе остеосинтеза. Стяжки удаляют, разрезая их скальпелем или перекусывая кусачками, затем пластину закрепляют к кости оставшимися винтами. Заключение. Хомуты-стяжки обладают многими преимуществами: они доступны, дешевы, не теряют своих механических свойств после стерилизации, позволяют надежно удерживать отломки костей во время репозиции, рентгенонегативны. Метод продемонстрировал удобство и надежность

СРАВНЕНИЕ ТРЕХ СПОСОБОВ ЛЕЧЕНИЯ ПЕРЕЛОМОВ ПЯТОЧНОЙ КОСТИ

Until now the problem of selecting a conservative or operative treatment option for calcaneal fractures and moreover the choice of the most optimal surgical procedure for such lesions have not been solved. Thus, comparative studies in this area is one of the most important tasks of the modern traumatology. Purpose of the study — to compare treatment outcomes, pattern and complications rate following the use of three treatment options for calcaneal fractures. Material and Methods. The authors analyzed treatment outcomes of 95 patients from 2013 till 2016. Mean age of patients was 39.04±12.51 years. Patients were divided into three groups: group 1 consisted of 41 patients with 54 fractures who underwent functional conservative treatment; group 2 consisted of 18 patients with 22 fractures treated by open reduction and plate fixation; group 3 consisted of 36 patients with 40 fractures treated by minimally invasive reduction and intramedullary fixation. Groups did not differ in respect of risk factors rate and rate of surgical risks under ABCDEF scale. Outcomes were evaluated basing on roentgenological criteria of reduction, complications rate and the functional scales FFI (Foot Function Index) and LEFS (Lower Extremity Functional Score). Results. Mean follow up was 20.8±9.0 months. Catamnesis was controlled in 68 out of 95 patients (71.6%). Variances were observed for all criteria of reduction quality between group 1 (no reduction) and groups 2 and 3. Groups 2 and 3 demonstrated similar criteria in respect of reduction quality of posterior articular surface, restoration of height and axis of calcaneus (р0.05). FFI and LEFS scores in group 1 were inferior to results in groups 2 and 3 (р0.05) at 6 and 12 months follow up. At 24 months follow up the variances persisted for mean values but were not statistically significant (р0.05). No differences between groups 2 and 3 were observed during all follow up terms (р0.05). Sum rate of complications in wound healing in group 2 was significantly higher than in groups 1 and 3 (р = 0.033). Conclusion. Any of the described options of surgical treatment resulted in an earlier functional restoration after calcaneal fractures as compared to conservative treatment. Reduction quality and late functional outcomes did not vary between the study groups, however, the rate of complications for wound healing in the group with open internal fixation was higher.Актуальность. Вопросы выбора консервативного или оперативного лечения при переломах пяточной кости, а тем более выбора оптимального метода хирургического лечения этих переломов, окончательно не решены. Проведение сравнительных исследований в этой области является одной из важных задач современ-ной травматологии. Цель исследования — сравнить функциональные результаты, характер и частоту осложнений при примене-нии трех способов лечения переломов пяточной кости. Материал и методы. Представлены результаты лечения 95 пациентов, проходивших лечение с 2013 по 2016 г. Средний возраст пациентов составил 39,04±12,51 лет. Пациентов разделили на три группы: группу 1 составил­ 41 пациент с 54 переломами после функционального консервативного лечения; группу 2 — 18 паци-ентов с 22 переломами после открытой репозиции и накостного остеосинтеза; группу 3 — 36 пациентов с 40 переломами после миниинвазивной репозиции и остеосинтеза штифтом. Группы не отличались по частоте встречаемости факторов риска неблагоприятных исходов и степени хирургического риска по шкале ABCDEF. Оценку результатов производили на основании рентгенологических критериев репозиции, частоты осложне-ний и показателей функциональных шкал FFI (Foot Function Index) и LEFS (Lower Extremity Functional Score). Результаты. Средний срок наблюдения составил 20,8±9,0 мес. Катамнез отслежен у 68 пациентов из 95 (71,6%). Разницу по всем показателям качества репозиции наблюдали между группой 1, где репозиция не проводилась, и группами 2 и 3 (р0,05). Группы 2 и 3 были одинаковы по качеству репозиции задней сус­ тавной площадки, восстановлению высоты и оси пяточной кости (р0,05). Показатели FFI и LEFS в группе 1 уступали показателям в группах 2 и 3 (р0,05) на сроках 6 и 12 мес. На сроке в 24 мес. различия сохранялись в средних значениях, но не были статистически значимыми (р0,05). Различий между группами 2 и 3 не вы-явлено на всех сроках наблюдения (р0,05). Суммарная частота осложнений заживления раны в группе 2 была значимо выше, чем в группах 1 и 3 (р = 0,033). Выводы. Каждый из представленных видов оперативного лечения по сравнению с консервативным по-зволяет быстрее восстановить функцию после перелома пяточной кости. Применение минимально инвазив-ной репозиции и остеосинтеза штифтом не уступает по функциональным результатам открытой репозиции и накостной фиксации, но несет меньший риск осложнений при заживлении раны

Vertex Operators for Closed Superstrings

We construct an iterative procedure to compute the vertex operators of the closed superstring in the covariant formalism given a solution of IIA/IIB supergravity. The manifest supersymmetry allows us to construct vertex operators for any generic background in presence of Ramond-Ramond (RR) fields. We extend the procedure to all massive states of open and closed superstrings and we identify two new nilpotent charges which are used to impose the gauge fixing on the physical states. We solve iteratively the equations of the vertex for linear x-dependent RR field strengths. This vertex plays a role in studying non-constant C-deformations of superspace. Finally, we construct an action for the free massless sector of closed strings, and we propose a form for the kinetic term for closed string field theory in the pure spinor formalism.Comment: TeX, harvmac, amssym.tex, 41 pp; references adde

Exponential distribution of long heart beat intervals during atrial fibrillation and their relevance for white noise behaviour in power spectrum

The statistical properties of heart beat intervals of 130 long-term surface electrocardiogram recordings during atrial fibrillation (AF) are investigated. We find that the distribution of interbeat intervals exhibits a characteristic exponential tail, which is absent during sinus rhythm, as tested in a corresponding control study with 72 healthy persons. The rate of the exponential decay lies in the range 3-12 Hz and shows diurnal variations. It equals, up to statistical uncertainties, the level of the previously uncovered white noise part in the power spectrum, which is also characteristic for AF. The overall statistical features can be described by decomposing the intervals into two statistically independent times, where the first one is associated with a correlated process with 1/f noise characteristics, while the second one belongs to an uncorrelated process and is responsible for the exponential tail. It is suggested to use the rate of the exponential decay as a further parameter for a better classification of AF and for the medical diagnosis. The relevance of the findings with respect to a general understanding of AF is pointed out

Instanton Calculations for N=1/ 2 super Yang-Mills Theory

We study (anti-) instantons in super Yang-Mills theories defined on a non anticommutative superspace. The instanton solution that we consider is the same as in ordinary SU(2) N=1 super Yang-Mills, but the anti-instanton receives corrections to the U(1) part of the connection which depend quadratically on fermionic coordinates, and linearly on the deformation parameter C. By substituting the exact solution into the classical Lagrangian the topological charge density receives a new contribution which is quadratic in C and quartic in the fermionic zero-modes. The topological charge turns out to be zero. We perform an expansion around the exact classical solution in presence of a fermionic background and calculate the full superdeterminant contributing to the one-loop partition function. We find that the one-loop partition function is not modified with respect to the usual N=1 super Yang-Mills.Comment: 27 pages, harmvac, Redone the computation of topological charge, a section has been rewritten and references adde