29 research outputs found
Gravitational Instability in Radiation Pressure Dominated Backgrounds
I consider the physics of gravitational instabilities in the presence of
dynamically important radiation pressure and gray radiative diffusion, governed
by a constant opacity, kappa. For any non-zero radiation diffusion rate on an
optically-thick scale, the medium is unstable unless the classical gas-only
isothermal Jeans criterion is satisfied. When diffusion is "slow," although the
dynamical Jeans instability is stabilized by radiation pressure on scales
smaller than the adiabatic Jeans length, on these same spatial scales the
medium is unstable to a diffusive mode. In this regime, neglecting gas
pressure, the characteristic timescale for growth is independent of spatial
scale and given by (3 kappa c_s^2)/(4 pi G c), where c_s is the adiabatic sound
speed. This timescale is that required for a fluid parcel to radiate away its
thermal energy content at the Eddington limit, the Kelvin-Helmholz timescale
for a radiation pressure supported self-gravitating object. In the limit of
"rapid" diffusion, radiation does nothing to suppress the Jeans instability and
the medium is dynamically unstable unless the gas-only Jeans criterion is
satisfied. I connect with treatments of Silk damping in the early universe. I
discuss several applications, including photons diffusing in regions of extreme
star formation (starburst galaxies & pc-scale AGN disks), and the diffusion of
cosmic rays in normal galaxies and galaxy clusters. The former (particularly,
starbursts) are "rapidly" diffusing and thus cannot be supported against
dynamical instability in the linear regime by radiation pressure alone. The
latter are more nearly "slowly" diffusing. I speculate that the turbulence in
starbursts may be driven by the dynamical coupling between the radiation field
and the self-gravitating gas, perhaps mediated by magnetic fields. (Abridged)Comment: 15 pages; accepted to Ap
Large mixing angle oscillations as a probe of the deep solar interior
We re-examine the sensitivity of solar neutrino oscillations to noise in the
solar interior using the best current estimates of neutrino properties. Our
results show that the measurement of neutrino properties at KamLAND provides
new information about fluctuations in the solar environment on scales to which
standard helioseismic constraints are largely insensitive. We also show how the
determination of neutrino oscillation parameters from a combined fit of KamLAND
and solar data depends strongly on the magnitude of solar density fluctuations.
We argue that a resonance between helioseismic and Alfven waves might provide a
physical mechanism for generating these fluctuations and, if so,
neutrino-oscillation measurements could be used to constrain the size of
magnetic fields deep within the solar radiative zone.Comment: 13 pages, LaTeX file using AASLaTeX, 6 figures included. Improved
version including the new KamLAND data. To appear in APJ letter
Economic Reforms in Hungary and Bulgaria and the Reaction to them in the USSR (Late 1950s — First Half of the 1970s)
Поступила в редакцию: 29.07.2021. Принята к печати: 12.10.2021.Submitted: 29.07.2021. Accepted: 12.10.2021.В статье проанализированы экономические реформы в Венгрии и Болгарии в конце 1950-х — начале 1970-х гг., а также реакция СССР на происходившие изменения в этих странах. Источниками для исследования стали документы посольств СССР в Венгерской Народной Республике (ВНР) и Народной Республике Болгария (НРБ), информационные записки советских экономистов, донесения спецслужб и материалы встреч и переговоров на высшем партийном и государственном уровне. Делается вывод, что значительная роль в запуске и сворачивании реформ принадлежала политическим лидерам Венгрии и Болгарии, что, на уровне принятия решений, отличало эти реформы от аналогичных в других странах социалистического лагеря. Авторы показывают, что переход на хозрасчетные отношения в ВНР и НРБ не решил целого ряда экономических проблем, а, напротив, спровоцировал отход от социалистических принципов и усиление рыночных элементов. Это привело к росту объема внешнего долга Венгрии и Болгарии, главным образом капиталистическим странам, что вызвало беспокойство со стороны советского руководства. Кремль, до того проводивший политику отстраненного наблюдения, фактически заставил Т. Живкова и Я. Кадара свернуть экономические реформы. В каждом случае Москва предложила индивидуальные решения: в Болгарии хозяйственная самостоятельность предприятий завершилась после того, как СССР погасил внутренний долг страны, а в Венгрии — после беседы Л. И. Брежнева с Я. Кадаром. Авторы считают, что непосредственным инициатором сворачивания реформ в ВНР и НРБ был узкий круг советских руководителей, которые осознали бесперспективность внедрения рыночных механизмов в социалистическую экономику и запустили в начале 1970-х гг. масштабный пересмотр концепции развития мировой системы социализма.This article analyses economic reforms in Hungary and Bulgaria between the late 1950s and early 1970s, as well as the reaction of official Moscow to the changes in these countries. The main sources for this article were documents of the Soviet embassies in the HPR and the PRB, briefing notes of Soviet economists, reports of special services and materials of meetings and negotiations at the highest party and state level. The authors conclude that a significant role in the launch and curtailment of reforms belonged to the political leaders of Hungary and Bulgaria — Ya. Kadar, the first secretary of the Central Committee of the HSWP, and T. Zhivkov, the General Secretary of the Central Committee of the BCP, Chairman of the Council of Ministers of the PRB. Therefore, at the level of decision-making, these reforms differed from similar ones in other countries of the socialist camp. The authors demonstrate that the transition to self-supporting relations in the HPR and PRB did not solve a number of economic problems, but, on the contrary, provoked a departure from socialist principles and the strengthening of market elements. This circumstance led to an increase in the volume of external debt of Hungary and Bulgaria, mainly to capitalist countries, which caused concern on the part of the Soviet leadership. Therefore, the Kremlin, which had previously pursued a policy of detached observation, forced Zhivkov and Kadar to curtail economic reforms. At the same time, Moscow offered individual solutions in each case. In Bulgaria, for example, the economic independence of enterprises ended after the USSR repaid the country’s internal debt, and in Hungary after Brezhnev’s conversation with Kadar. The authors believe that the direct initiator of the curtailment of reforms in the HPR and the PRB was a rather narrow circle of Soviet leaders who realised the futility of introducing market mechanisms into the socialist economy and launched a large-scale revision of the concept of the development of the world system of socialism in the early 1970s.Статья подготовлена при финансовой поддержке РНФ, проект № 17-18-01728-П в рамках проекта «“Мировая система социализма” и глобальная экономика в середине 1950-х — середине 1970-х гг.: эволюция теории и практики экономического и технологического лидерства СССР».The article was prepared with the financial support of the Russian Science Foundation, project 17-18-01728-P within the framework of the project “The World System of Socialism and the Global Economy between the mid-1950s and mid-1970s: Evolution of the Theory and Practice of Economic and Technological Leadership of the USSR”
БИОЛОГИЧЕСКАЯ ЭФФЕКТИВНОСТЬ РАЗЛИЧНЫХ ПРЕПАРАТОВ ПРОТИВ СЕМЕННОЙ ИНФЕКЦИИ СОСУДИСТОГО БАКТЕРИОЗА КАПУСТЫ
Black rot (pathogen – Xanthomonas campestris pv. campestris) is one of the most harmful diseases of brassicas. Seedlings growing in trays in greenhouse can meet rapid spreading of the pathogen and heavy yield loss even at very low seed infection level. This work was targeted on efficiency comparison for different plant protection agents against black root infection in seeds. Antibacterial effect of the agents was tested in vitro by well diffusion, direct placement of the agent onto bacterial lawn, and by incubation of bacterial suspension with the agents. Biological efficiency of the agents against seed infection was tests by seed soaking or by wet treatment. High antibacterial effect against black rot pathogen in vitro was shown for bacteriophage cocktail, Biocomposite-correct, Zeroxxe, Peroxyacetic acid (NUK15), Ps 11, and Kocide 2000. Highest biological efficiency against seed infection by black rot was shown for bacteriophage cocktail, Biocomposite-correct, Zeroxxe, Peroxyacetic acid (NUK15), and Kocide 2000.Сосудистый бактериоз (возбудитель – Xanthomonas campestris pv. campestris) – одна из наиболее опасных болезней капустных культур. При выращивании рассадным методом даже небольшая зараженность семян приводит к массовому распространению патогена и, в дальнейшем, к значительным потерям урожая в поле. Целью работы было сравнительное испытание эффективности препаратов различного происхождения в отношении семенной инфекции сосудистого бактериоза капусты. Проводили оценку антибактериальной активности препаратов in vitro методом диффузии из лунок, методом нанесения капли препарата на газон бактерий, а также методом совместной инкубации суспензий испытываемых препаратов и патогена. Оценку биологическую эффективности препаратов против семенной инфекции сосудистого бактериоза капусты проводили методами замачивания семян и обработки с увлажнением. Показано, что сильной антибактериальной активностью по отношению к возбудителю сосудистого бактериоза капусты в условиях in vitro обладали консорциум бактериофагов, Биокомпозит-коррект, Зерокс, НУК 15, Ps 11 и Косайд 2000. Наибольшую биологическую эффективность в подавлении семенной инфекции сосудистого бактериоза показали бактериофаги, Биокомпозит-коррект, НУК 15, Зерокс и Косайд 2000
Cornering Solar Radiative-Zone Fluctuations with KamLAND and SNO Salt
We update the best constraints on fluctuations in the solar medium deep
within the solar Radiative Zone to include the new SNO-salt solar neutrino
measurements. We find that these new measurements are now sufficiently precise
that neutrino oscillation parameters can be inferred independently of any
assumptions about fluctuation properties. Constraints on fluctuations are also
improved, with amplitudes of 5% now excluded at the 99% confidence level for
correlation lengths in the range of several hundred km. Because they are
sensitive to correlation lengths which are so short, these solar neutrino
results are complementary to constraints coming from helioseismology.Comment: 4 pages, LaTeX file using RevTEX4, 6 figures include
Ислам и уростома: современный взгляд через призму религиозно-традиционной правовой системы
Patients who practice Islam often refuse the proposed type of treatment for malignant neoplasms, citing religious reasons. Most fear that complete or partial non-retention of urine, the presence of a urostoma (ileal conduit) will violate their ritual purity and, as a result, their religious duties. The consequence of such refusal of treatment may be a lower quality of life, compared with patients of other faiths. Unfortunately, a low awareness of religious responsibilities among surgeons performing pelvic exentesis, cystectomy, prostatectomy, may prevent a full-fledged discussion of these issues before surgery. The presented review of the literature examined studies, legal aspects, and religious arguments that assist doctors in choosing treatment tactics for patients.Пациенты, исповедующие ислам, зачастую отказываются от предложенного вида лечения по поводу злокачественного новообразования, ссылаясь на религиозные причины. Большинство опасаются, что полное или частичное недержание мочи, наличие уростомы (подвздошного кондуита) нарушат их ритуальную чистоту и, как следствие, их религиозные обязанности. Следствием такого отказа от лечения может явиться более низкое качество жизни по сравнению с пациентами других конфессий. К сожалению, низкая осведомленность о религиозных обязанностях среди хирургов, выполняющих экзентерации таза, цистэктомии, простатэктомии, может препятствовать полноценному обсуждению этих вопросов до операции. В представленном обзоре рассмотрены исследования, правовые аспекты, религиозные доводы, помогающие врачам в выборе тактики лечения пациентов
THE BIOLOGICAL EFFECTIVENESS OF VARIOUS PREPARATIONS AGAINST SEED INFECTION OF CABBAGE BLACK ROT
Black rot (pathogen – Xanthomonas campestris pv. campestris) is one of the most harmful diseases of brassicas. Seedlings growing in trays in greenhouse can meet rapid spreading of the pathogen and heavy yield loss even at very low seed infection level. This work was targeted on efficiency comparison for different plant protection agents against black root infection in seeds. Antibacterial effect of the agents was tested in vitro by well diffusion, direct placement of the agent onto bacterial lawn, and by incubation of bacterial suspension with the agents. Biological efficiency of the agents against seed infection was tests by seed soaking or by wet treatment. High antibacterial effect against black rot pathogen in vitro was shown for bacteriophage cocktail, Biocomposite-correct, Zeroxxe, Peroxyacetic acid (NUK15), Ps 11, and Kocide 2000. Highest biological efficiency against seed infection by black rot was shown for bacteriophage cocktail, Biocomposite-correct, Zeroxxe, Peroxyacetic acid (NUK15), and Kocide 2000
Islam and urostoma: a modern view through the prism of a religiously traditional legal system
Patients who practice Islam often refuse the proposed type of treatment for malignant neoplasms, citing religious reasons. Most fear that complete or partial non-retention of urine, the presence of a urostoma (ileal conduit) will violate their ritual purity and, as a result, their religious duties. The consequence of such refusal of treatment may be a lower quality of life, compared with patients of other faiths. Unfortunately, a low awareness of religious responsibilities among surgeons performing pelvic exentesis, cystectomy, prostatectomy, may prevent a full-fledged discussion of these issues before surgery. The presented review of the literature examined studies, legal aspects, and religious arguments that assist doctors in choosing treatment tactics for patients