8,121 research outputs found
Hot Topics from the BABAR Experiment
With a sample of about 384 million BBbar pairs recorded with the BABAR
detector, we search for the flavor-changing charged current transition B+ ->
\tau\nu and perform an amplitude analysis of the effective flavor-changing
neutral current transition B+ -> \phi(1020)K*(892)+. We also extend our search
for other K* final states in the decay B0 -> phi(1020)K*0 with a large K*0 ->
K+pi- invariant mass. Two samples of events with one reconstructed hadronic B
decay or one reconstructed semileptonic B decay are selected, and in the recoil
a search for B+ -> \tau\nu is performed. We find a 2.6 sigma (3.2 sigma not
including expected background uncertainty) excess in data which can be
converted to a preliminary branching fraction central value of BR(B+ -> \tau\nu
) = (1.20 +0.40-0.38 +0.29-0.30 +-0.22) 10^-4. With the decay B+- ->
\phi(1020)K*(892)+-, twelve parameters are measured, where our measurements of
f_L=0.49+-0.05+-0.03, f_perp=0.21+-0.05+-0.02, and the strong phases point to
the presence of a substantial helicity-plus amplitude from a presently unknown
source.Comment: 14 pages, 33 postscript figures, proceedings of the 5th Flavor
Physics And CP Violation Conference (FPCP 2007) C07/05/1
Transition form factors of B decays into p-wave axial-vector mesons in the perturbative QCD approach
The form factors are studied in perturbative QCD approach
( denote a vector meson and two kinds of p-wave axial-vector mesons:
and states, respectively.). The form factors are directly
studied in the large recoiling region and extrapolated to the whole kinematic
region within the dipole parametrization. Adopting decay constants with
different signs for the two kinds of axial-vectors, we find that the two kinds
of form factors have the same sign. The two strange mesons
and mix with each other via the SU(3) symmetry breaking effect. In
order to reduce the ambiguities in the mixing angle between and
, we propose a model-independent way that utilizes the B decay data.
Most of the branching fractions of the semilteptonic decays
are of the order , which still need experimental tests in the on-going
and forthcoming experiments.Comment: 22 pages, 7 figure
Study of Polarization in B -> VT Decays
In this paper, we examine B -> VT decays (V is a vector and T is a tensor
meson), whose final-state particles can have transverse or longitudinal
polarization. Measurements have been made of B -> \phi K_2^*, and it is found
that fT/fL is small, where fT (fL) is the fraction of transverse (longitudinal)
decays. We find that the standard model (SM) naively predicts that fT/fL << 1.
The two extensions of the naive SM which have been proposed to explain the
large fT/fL in B -> \phi K^* -- penguin annihilation and rescattering -- make
no firm predictions for the polarization in B -> \phi K_2^*. The two
new-physics scenarios, which explain the data in B -> \pi K and the \phi (\rho)
K^* polarization measurements, can reproduce the fT/fL data in B -> \phi K_2^*
only if the B -> T form factors obey a certain hierarchy. Finally, we present
the general angular analysis which can be used to get helicity information
using two- and three-body decays.Comment: 15 pages, latex, 3 figures (enclosed), several changes made,
conclusions unchanged, publication info adde
The and decays in perturbative QCD approach
In perturbative QCD approach, we investigate the and decays,
which include the Cabibbo-Kobayashi-Maskawa (CKM) favored decays and the
Cabibbo-Kobayashi-Maskawa-suppressed decays, where T denotes a light tensor
meson. From our calculation, we find that the nonfactorizable emission diagrams
and the annihilation type diagrams are important, especially for those color
suppressed channels. For those decays with a tensor meson emitted, the
factorizable emission diagrams vanish owing to the fact that a tensor meson can
not be produced through the local (V-A) or tensor current. The numerical
results show that the predictions for the branching ratios of considered
charmed B decays are in the range of to for those
CKM-favored decays (governed by ) and in the range of to
for those CKM-suppressed decays (governed by ). We also
predict large transverse polarization contributions in many of the decay channels.Comment: 30 pages, 3 figures, typos correctet in Figs. 1 and
Radial increment dynamics in Pinus sylvestris stands within the Northern Steppe of Ukraine
The parameters of periodic increment (5-years) and peculiarities of its change depending on age, diameter, height and volume of trunk of Scots pine are determined. The influence of climate conditions (air temperature and precipitation) on the dynamics of radial increment change of Scots pine trees are established. The results of experimental studies, obtained from 20 temporary sample plots of pine stands within the Northern Steppe of Ukraine are presented. We conducted an estimate of radial increment of Scots pine trunks as a basis for development of normative and information support for assessment of biotic productivity of this category of forest. All selected sample trees had different age and biometric parameters. The age of sample trees ranged from 9 to 90 years; diameter at breast height – from 4.0 to 41.7 cm; height – from 4.2 to 30.0 m, trunk volume – from 0.002 to 1.748 m3. It is found that the radial increment of pine stem was significantly dependent on tree age. The highest values of radial increment of Scots pine trees were observed for trees aged up to 20 years. With increasing age, radial increment had a decreasing trend, including 90-year old trees. Regression models of the dependence of radial increment of pine trees on the age and diameter are presented. In the article, the dependence of the values of radial increment of sample trees from types of forest are demonstrated. The highest values of Scots pine radial increment was observed in sugruds and gruds, which were presented in tree samples of 20 years. Comparative analysis of radial increment change in the trees of one age category, which grew in different conditions, was conducted. The older trees had the maximum increment in the conditions of dry sugrud, and the minimum increment in conditions of fresh subor. Also in this article we used generalized chronology of Scots pine radial increment reflecting regional variability of growth in pine trees. The results supplemented the research obtained earlier with new data on the dependence of the pine radial growth rate on forest-biometric parameters. These experimental data, their graph-analytical evaluation yielded an information basis for modeling the radial increment of pine trees, created on the basis of dependence of this parameter on biometric indexes – age and diameter at breast height
Эвакуация акушерско-гинекологических больных, находящихся в критическом состоянии
Objective: to assess the results of evacuation of critically ill obstetric and gynecological patients by ground and air transports to improve the quality of a specialized medical aid on the basis of the technology developed by the Obstetric Resuscitative Advisory Center (ORAC). Subjects and methods. The study was based on the prospective and retrospective analysis of the results of evacuation of 358 critically ill obstetric and gynecological patients in the presence of severe gestosis (n=162), obstetric hemorrhages (n=74), abdominal (obstetric) sepsis (n=68), as well as pregnant women and puerparas with extragenital pathology (n=54) via ground (26.5%) and air (75.3%) transports by the workers of the ORAC in the period of 1998-2006. Results. Complex intensive care aimed at correcting major critical states, performed during evacuation by a resuscitative-advisory team, could provide the steady-state values of vital functions during transportation of obstetric and gynecological patients. Conclusion. A scheme has been developed for safe evacuation of critically ill obstetric and gynecological patients via ground and air transports by the ORAC workers. Key words: patient evacuation, gestosis, hemorrhage, sepsis, obstetrics, gynecology.Цель исследования — оценка результатов эвакуации больных в критическом состоянии с акушерско-гинекологичес-кой патологией наземным и воздушным транспортом для улучшения качества оказания специализированной медицинской помощи на основе технологии АРКЦ. Материал и методы. Работа основана на ретроспективном и проспективном анализе результатов эвакуации 358 пациенток с акушерско-гинекологической патологией в критическом состоянии на фоне тяжелых форм гестоза (162 случая), акушерских кровотечений (74), абдоминального (акушерского) сепсиса (68), а также у беременных и родильниц с экстрагенитальной патологией (54) наземным (26,5%) и воздушным (75,3%) транспортом силами акушерского реанимационно-консультативного центра за период 1998—2006 годы. Результаты исследования. Комплексная интенсивная терапия, направленная на коррекцию основных синдромов критического состояния, проводимая в процессе эвакуации реанимационно-консультативной бригадой, позволила обеспечить стабильные показатели жизненно-важных функций организма в процессе транспортировки больных с акушерско-гинекологической патологией. Заключение. Разработана схема безопасной эвакуации пациентов с акушерско-гинекологической патологией в критическом состоянии наземным и воздушным транспортом силами акушерского реанимационно-консультативного центра. Ключевые слова: эвакуация больных, гестоз, кровотечение, сепсис, акушерство и гинекология
Аналіз показників асиміляційної складової у структурі надземної фітомаси деревних порід степових лісостанів України
The purpose this research is to study the parameters of leaf (needle) share in the trees’ greenery fraction and the content of absolutely dry matter in fresh leaves of black locust and Scots pine. The leaf (needle) share in the trees greenery fraction and the content of absolutely dry matter were determined by their quantitative measures (weight and volume). The results of the research reveal that the leaf share in the structure of a tree’s greenery fraction has a broad range of values: 43.0–72.8% for black locust and 49.1–75.4% for Scots pine. The minimum value of this parameter was recorded for an overmature Robinia specimen of 41 years of age, while the maximum was for a 3-year-old tree. For pine trees the lowest values of the given parameter were registered for the spcimens aged 38, 49 and 84, the maximum – for 30–31-year-old trees. For both investigated species it should be noted that there is a consistent pattern indicated by the following trend line: with the increase of tree age, height and trunk diameter, there is a decrease of leaf share value in the trees’ greenery fraction. Such characteristic parameter as absolutely dry mass has a sufficient range of values from 0.321 to 0.524, with the extreme values for the trees belonging to the young stock group in the case of the black locust. The absolutely dry matter content in Scots pine needles showed a significant variability of values from 0.426 to 0.620. The trend line shows a tendency of increase in the value of absolutely dry matter mass in the leaves of both investigated species with the increase in the values of the tree taxation parameters. There is no statistically proven dependency of the parameter indicating leaf share in the trees greenery fraction on the age, trunk diameter and height of trees. The most important biometric indicator, which shows a moderate relationship with the greenery fraction of a tree is the average diameter of the trunk of model trees of the two studied species. This is confirmed by values of correlation coefficients. The indicator of greenery fraction is inversely dependent on the height, trunk diameter and tree age, i.e. the increase in the values of these parameters leads to the decrease in the share of the photosynthetic active component of trees of the studied tree species in the steppe zone. The value of leaf (needle) share in trees’ greenery fraction decreases with the increasing age, height and diameter values, which is quite natural. Correlation indices of absolutely dry matter according to age, height and diameter of sample trees have negative values, while the index of leaf (needle) share of trees’ greenery fraction has a direct correlation with all the studied influence factors. Подано результати досліджень асимілювальної складової надземної фітомаси – частка листя (хвої) та вміст абсолютно сухої речовини у листі (хвої) у фракції деревної зелені головних лісотвірних порід лісостанів Північного Степу України – Pinus sylvestris L. та Robinia pseudoacacia L. Значення показників частки листя (хвої) у структурі асимілювальної складової робінії звичайної та сосни звичайної перебувають у певному діапазоні, який демонструє їх залежність від основних таксаційних показників деревостанів. Спостерігається зменшення даного показника зі збільшенням віку та зі зростанням середнього діаметра та висоти стовбура для двох досліджуваних деревних порід. Виявлено тренди, що демонструють зміни значень вмісту абсолютно сухої речовини у листі робінії звичайної та у хвої сосни звичайної. Висока варіабельність абсолютних значень вмісту сухої речовини у листі робінії зафіксована за умов однакових значень віку, діаметра стовбура та висоти модельних дерев. Показники вмісту абсолютно сухої речовини у хвої сосни звичайної, навпаки, мають тенденцію до підвищення відносно досліджуваних таксаційних параметрів. Подано результати досліджень асимілювальної складової надземної фітомаси – частка листя (хвої) та вміст абсолютно сухої речовини у листі (хвої) у фракції деревної зелені головних лісотвірних порід лісостанів Північного Степу України – Pinus sylvestris L. та Robinia pseudoacacia L. Значення показників частки листя (хвої) у структурі асимілювальної складової робінії звичайної та сосни звичайної перебувають у певному діапазоні, який демонструє їх залежність від основних таксаційних показників деревостанів. Спостерігається зменшення даного показника зі збільшенням віку та зі зростанням середнього діаметра та висоти стовбура для двох досліджуваних деревних порід. Виявлено тренди, що демонструють зміни значень вмісту абсолютно сухої речовини у листі робінії звичайної та у хвої сосни звичайної. Висока варіабельність абсолютних значень вмісту сухої речовини у листі робінії зафіксована за умов однакових значень віку, діаметра стовбура та висоти модельних дерев. Показники вмісту абсолютно сухої речовини у хвої сосни звичайної, навпаки, мають тенденцію до підвищення відносно досліджуваних таксаційних параметрів.
Climatogenic reaction of Robinia pseudoacacia and Pinus sylvestris within Northern Steppe of Ukraine
Climatic changes in the environment are becoming more noticeable each year. Nonetheless, trends in the reaction of radial growth of forest trees to climate change should be studied in different climatic regions due to significant local variability in climatic conditions which are specific for any particular area. We conducted a correlation analysis of the relationship between the parameters of radial increment of black locust (Robinia pseudoacacia L.) and Scots pine (Pinus sylvestris L.) and meteorological factors of the environment in forest areas located in thenorthern steppe zone of Ukraine. We performed surveys in plantations of black locust, growing in hill slope and interfluve areas and also in sandy terrace plots of Scots pine. Over the period of intense vegetatative growth, black locust requires moisture 50% higher than the norm, and Scots pine 43% higher than the norm. It was determined that maximum increment for the studied plants occurred under the influence of a combination of factors involving reduction of the air temperature by 2.6–2.7 °С below the norm for black locust and by 2.3–2.5 °С for Scots pine. During the period of lower vegetative activity, Scots pine demonstrated lower sensitivity compared to black locust. This paper provides a statistical characteristic of the radial increment of trees in the conditions of changes in meteorological factors which limit their growth. The article provides data on multiple correlation of radial increment of the tree stands in relation to growth locations; demonstrates correlation dependency of radial increment of the studied trees on the precipitation and mean monthly temperatures over different time periods and during particular months. Radial increment of Scots pine exhibited most positive correlation with the total of precipitations throughout the period. For the stands of black locust, correlation coefficients were higher and distinguished by both positive and negative values. In the current increment of this species, a negative correlation relation was observed with the total precipitation in July, August and September, and positive correlation with the remaining months of the year. By contrast, radial increment of black locust and Scots pine positively correlated with air temperature during all time periods and particular months
Особенности продуктивности сосновых древостоев в лесонасаждениях Северной Степи Украины
The aim of this work is the comparative analysis of the productivity of Scots pines in pure and mixed plantations with main and accompanying species in the Northern Steppe of Ukraine We analysed the taxation parameters such as height, diameter, stand density, which vary with the age of the stand and composition of the plantation. Within the study area pines grow mainly in pure stands (81.9%). The share of mixed forest stands in the study area is only 18.1%. The analysis of representation of age structure showed the presence of the same proportion of the young age group in pure and mixed stands, the dominant share being taken up by middle-aged monoculture stands, and thus a smaller area taken up by mature and overmature pines. The average stand density per 1 ha in pure stands of all age groups is 17% higher than in mixed stands. The dynamics of variations of such biometric data as average height, diameter and density for the different compositions of Scots pine stands were measured for 14 age classes. The mean heights of the pure and mixed stands are vere close, while the average diameter gradually increased with age, reaching its maximum in overmature plantations. The research results showed that there is an excess of this parameter in the mixed compared with the pure stands. We did not find significant differences between middle age pure and mixed stands in accumulation of stand density. But pure pine stands show a clear tendency to dominate in wood accumulation in all age classes through the period of growth. The greatest difference between pure and mixed stands in the mean stand density was observed for those of middle-age. The average stand density in the pure stands was up to 32% higher than the mixed. The area distribution of Scots pine stands according to productivity was as follows. The largest area for both pure and mixed stands was occupied by trees of quality class I, which took up 54.3% of the total pure pine acreage and 41.9% of the mixed stand acreage. The second position was occupied by quality class II, which occupied 27.6% of total pure pine acreage and 36.6% of mixed stand acreage with the perecentage of total stand density at 23.6% and 35.1% respectively. In general, the value of the average stand density falls as the quality class decreases, and essentially depends on the composition of plantations: in pure stands, it is higher than in mixed. The investigated values of the biometric parameters are statistically significant for both the pure and the mixed stands. Проанализирована возрастная структура древостоев сосны обыкновенной (PinussylvestrisL.) в чистых и смешанных лесонасаждениях Северной Степи Украины. Показано превалирование доли средневозрастных монокультур сосны. Средний запас древесины на 1 га во всех исследуемых возрастных группах однопородных насаждений превышает таковую в смешанных максимум на 17%. Приведена динамика изменений биометрических показателей (высоты, диаметра и запаса древесины) для разных по составу сосновых насаждений. По сравнению со средней высотой, показатель средного диаметра имеет большую зависимость от возраста, что особенно характерно для древостоев смешанного типа. Наблюдается тенденция доминирования формирования древесины в чистых по составу насаждениях во всех исследуемых классах возраста на 3–32 %. Показано падение величины среднего запаса по мере снижения бонитетного класса, которое в чистых насаждениях выше, сравнительно со смешанными. Приведены статистически достоверные значения зависимости таксационных параметров древостоев от возраста, как в чистых, так и смешанных. Проанализирована возрастная структура древостоев сосны обыкновенной (PinussylvestrisL.) в чистых и смешанных лесонасаждениях Северной Степи Украины. Показано превалирование доли средневозрастных монокультур сосны. Средний запас древесины на 1 га во всех исследуемых возрастных группах однопородных насаждений превышает таковую в смешанных максимум на 17%. Приведена динамика изменений биометрических показателей (высоты, диаметра и запаса древесины) для разных по составу сосновых насаждений. По сравнению со средней высотой, показатель средного диаметра имеет большую зависимость от возраста, что особенно характерно для древостоев смешанного типа. Наблюдается тенденция доминирования формирования древесины в чистых по составу насаждениях во всех исследуемых классах возраста на 3–32 %. Показано падение величины среднего запаса по мере снижения бонитетного класса, которое в чистых насаждениях выше, сравнительно со смешанными. Приведены статистически достоверные значения зависимости таксационных параметров древостоев от возраста, как в чистых, так и смешанных.
Albedo of the soil cover as a factor of the temporal dynamics of readily available soil moisture in the technosols of the Nikopol manganese ore basin
The simulation of moisture content in Nikopol manganese ore basin technosols was performed using the Penman-Monteith approach and evaluate the role of the dependence
of soils surface albedo from the humidity in the intensity of evapotranspiration. The sod lithogenic soils on loess-like loam and pedozem were chosen as the objects of the investigation. The research was conducted during 2012–2014 years at the investigation station of
the remediation within Nikopol manganese ore basin (city Pokrov, Ukraine). The evapotranspiration from the soil surface was calculated by means of Penman-Monteith equation.
Root zone moisture depletion is evaluated as the difference between soil water content at field capacity (pF = 2.3) and actual soil water content. The Ks value which is a water stress
factor equals 1.0 as long as soil water content is higher than readily available water. If soil
water content is lower than readily available water, Ks decreases linearly from one to zero
according to total available soil water consumed. The soil water balance is performed in ISAREG with a daily time. The evaluation of readily available water content was carried out based on Penman-Monteith model taking into account meteorological data, technosols water-physical properties and the dependence of soil surface albedo on soil humidity. The color of the surface of the sod-lithogenic soil on the loess-like loam varies from yellow (2.5Y 4/2) in wet condition to yellow-red (10YR 6/5) in the dry condition. Albedo of this soil depended
on the humidity varies in the range 0.17–0.31. The surface color of the pedozem varies from very dark gray (10YR 3/1) in wet condition to light-gray (2.5YR 6/2) in the dry condition. Albedo of this soil depended on the humidity varies in the range 0.10–0.31. There is a linear
relationship between the moisture content in the soil and albedo of the soil surface. Albedo changes along with the humidity are most significant in the sod-lithogenic soils on loess-like loams. This is confirmed by the greatest regression coefficient. Albedo changes along with
the moisture content are least significant in the pedozem. The distributionі of this index for different teсhnosols are characterized by a high level of similarity of shape due to the fact that the overall climate factors are crucial in shaping the dynamics of moisture. The distributions can be most good represented as a complex mixture of normal distributions. It was found that water supplies monitoring before the start of the growing season can provide valuable information necessary for the selection of crops for cultivation in the current year. The results indicate the urgency of measures to save the winter rainfall on the fields
- …