Periodicity Search on X-Ray Bursts of SGR J1935+2154 Using 8.5 yr of Fermi/GBM Data

We performed a systematic search for X-ray bursts of the SGR J1935+2154 using the Fermi Gamma-ray Burst Monitor continuous data dated from 2013 January to 2021 October. Eight bursting phases, which consist of a total of 353 individual bursts, are identified. We further analyze the periodic properties of our sample using the Lomb–Scargle periodogram. The result suggests that those bursts exhibit a period of ∼238 days with a ∼63.2% duty cycle. Based on our analysis, we further predict two upcoming active windows of the X-ray bursts. Since 2021 July, the beginning date of our first prediction has been confirmed by the ongoing X-ray activities of the SGR J1935+2154.

Interannual variability of net ecosystem carbon production and its climatic and biotic mechanism during 2005-2018 in a rain-fed maize ecosystem

The interannual variation (IAV) of net ecosystem carbon production (NEP) plays an important role in understanding the mechanisms of the carbon cycle in the agriculture ecosystem. In this study, the IAV of NEP, which were expressed as annual values and anomalies, and its climatic and biotic controls mechanism, were investigated based on an eddy covariance dataset of rain-fed spring maize during 2005–2018 in the northeast of China. The annual NEP was 270±115 g C m−2yr −1. Annual values and anomalies of NEP were positively correlated with that of precipitation (PPT), gross ecosystem production (GEP) and daily maximum NEP (NEPmax). Annual anomalies of NEP were dominantly and positively controlled by the soil water content (SWC) through GEP and the soil temperature (Ts) through RE. In comparison, annual anomalies of NEP were dominantly and negatively controlled by summer VPD through the NEPmax, positively adjusted by spring precipitation and the effective accumulative temperature through the beginning date (BDOY) of the affecting carbon uptake period (CUP), and by autumn precipitation and leaf area index through the end date (EDOY) of the affecting CUP. Residues restrained the carbon release at the beginning of the year, and accelerated the carbon release at the end of the year. Our results hightlight that NEP might be more sensitive to the change of water condition (such as PPT, SWC and VPD) induced by the climate changes.

Phenological study of sugar apple (Annona squamosa L.) in dystrophic yellow latosol under the savanna conditions of Roraima

Sugar apple (Annona squamosa L.) is a commercially significant fruit species due to its nutritional qualities. The state of Roraima has excellent soil and climatic conditions for the cultivation of the species. However, no studies on the phenological behavior of this plant have been reported in the literature. In this context, the objective of this work was to investigate the vegetative and reproductive phenological behavior of sugar apple under the savanna conditions of the state of Roraima. The experiment was carried out in four seasons of the year (2014/2014 and 2015/2015 rainy season and 2014/2015 and 2015/2016 Summer). Production pruning was carried out in February 2014 (2014.1 cycle), September 2014 (2014.2 cycle), February 2015 (2015.1 cycle) and September 2015 (2015.2 cycle). Forty plants were monitored during the experiment and evaluated every three days for the following variables: beginning date of bud swelling; duration of flowering; and fruit harvest time. From the observed data, the periods (days) between each phenological stage were calculated: pruning/bud swelling; pruning/beginning of flowering; bud swelling/anthesis; pruning/anthesis; anthesis/beginning of fruit harvest; duration of fruit harvest, and crop cycle (production pruning/harvest). The duration of the cycle, from the production pruning to the harvest varied according to the productive period, recording 146 days for the 2014.1 cycle and 127 days for the 2014.2 cycle, which proves that the phenological behavior of the species is influenced by climatic conditions.

NDWI-BASED TECHNIQUE FOR DETECTION OF CHANGE DATES OF THE GROWING SEASONS IN RUSSIAN SUBARCTIC

The paper describes a technique for automated analysis of the annual graphs of Normalized Difference Water Index, which enables to allocate framing dates of the spring, summer and autumn growing seasons. The approach proposed and used for detection of growing season dates allows to detect beginning and ending dates for summer season (when the surface air temperature is above +10 °C), in addition to the detection of beginning date for spring season and ending date for autumn season (when the temperature is above +5 °C), as it described by some authors. We describe general idea of the analysis of NDWI annual graphs and some collisions in the graph data, which are possible when the graph is derived from the satellite imagery time series.

Extralegal Violence: The Ku Klux Klan In The Reconstruction Era

This article is a response to the Equal Justice Initiative’s 2015 report on lynching, which aimed to provide a comprehensive account of racial terror since 1877. Although the study encompassed three years before the commonly used beginning date of research on lynching, the author argues that it omitted a great number of cases from the Reconstruction era (1865-1877). In this essay, she evaluates testimonial evidence from the 13 volumes of the Report of the Joint Select Committee to Inquire into the Condition of Affairs in the Late Insurrectionary States published by the U.S. Congress in 1872, citing specific cases of atrocities committed by the Ku Klux Klan in the years following the Civil War. A close examination of these reports reveals that the level of extralegal violence inflicted on African Americans in the Reconstruction era has been severely underestimated. Researchers are called to extend their investigations of lynching to include this period of history in order to develop a more truthful account of racial terror in this country.

Variation of Main Phenophases in Phenological Calendar in East China and Their Response to Climate Change

Based on the phenological data from China Phenological Observation Network, we compiled the phenological calendars of 3 phenological observation stations (Shanghai, Nanjing, and Hefei) in East China for 1987–1996 and 2003–2012 according to the sequences of mean phenophases. We calculated the correlated coefficient and the root mean square error (RMSE) between phenophases and the beginning of meteorological seasons to determine the beginning date of phenological season. By comparing new phenological calendars with the old ones, we discussed the variation of phenophases and their responses to temperature. The conclusions are as follows. (1) The beginning dates of spring and summer advanced, while those of autumn and winter delayed. Thus, summers got longer and winters got shorter. (2) The beginning time of the four phenological seasons was advancing during 1987–1996, while it was delaying during 2003–2012. (3) Most spring and summer phenophases occur earlier and most autumn and winter phenophases occur later in 2003–2012 than in 1987–1996. (4) The beginning time of phenological seasons was significantly correlated with temperature. The phenological sensitivities to temperature ranged from −6.49 to −6.55 days/°C in spring, −3.65 to −5.02 days/°C in summer, 8.13 to 10.27 days/°C in autumn, and 4.76 to 10.00 days/°C in winter.

Temperature Characteristics and Spring Frost Risk in the Sour Cherry (Prunus Cerasus L.) Blooming Period in 1985–2010

The aim of the paper is an attempt to present the relationships between sour cherry (Prunus cerasus L.) blooming time, climatic conditions and spring frost risk in western Poland (Great Poland Lowland). Air temperature indices from meteorological stations in Przybroda and Poznań for the period 1985-2010 representing contemporary climate warming were used. ‘English Morello’ sour cherry phenological records for the period 1985-2010 were collected at the Research Station of Poznań University of Life Sciences located in Przybroda. The earliest end of blooming was observed on 2nd of May 1999, and the latest one on 26th of May 1987. The average period of sour cherry blooming was between 30th April and 12th May. During 50% of the years the blooming period lasted from 11 to 15 days. Mean monthly temperature in Przybroda varied from -1.1°C in January to 19.6°C in July. A significant relationship between the beginning date of cherry blooming and the beginning of the thermal vegetation period was found. Variability of the index explained more than 50% of variability in the first dates of cherries blooming (coefficient of determination R2 = 0.505 is significant on the level p < 0.05). The beginning of blooming was also significantly (p < 0.05) correlated with mean April temperature, which could explain about 43% of variability in the dates of the first bloom. An increase in April temperature by 1.0°C caused earlier blooming by about 2.8 days. During the period of 1985-2010 a significant increase in April temperature was observed (in Poznań 0.79°C per decade). It had an effect on advanced dates of the beginning of sour cherry blooming of about 3 days per decade. In 26 of the years the last frost occurred 4 times (15% of seasons) during the blooming phenological phase or later in Przybroda. Frost occurred 10 days before blooming started and during blooming in 54% of the years.

Changes of The Thermic Seasons in Warsaw in The Period 1933–2004

The beginning dates and the lengths of thermic seasons in Warsaw (1951-2004) were analysed. These characteristics of seasons are very variable, especially in winter. The changes of winter length influence strongly the dates and length of adjacent seasons, that is, of early winter and early spring. The current warming is best visible exactly during these seasons: winter becomes shorter, while early winter and – to an even longer degree – early spring become longer. The period of spring, summer and autumn is characterised by grater stability. These seasons showed a very weak tendency to change on even its lack, both as regards the length and the beginning date.