Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser.

Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we identify significant structural dynamics with characteristic isotope effects in H2O2+, D2O2+, and HDO2+, such as asymmetric bond elongation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. A method to disentangle the sequences of events taking place upon the consecutive absorption of two x-ray photons is described. The obtained deep look into structural properties and dynamics of dissociating water isotopologues provides essential insights into the underlying mechanisms.

Plastic energy allocation toward life-history functions in a consumer-resource interaction : Analyzing the temporal patterns of the consumer-resource dynamics.

Various environmental alterations resulting from the current global change compromise the persistence of species in their habitual environment. To cope with the obvious risk of extinction, plastic responses provide organisms with rapid acclimatization to new environments. The premise of plastic rescue has been theoretically studied from mathematical models in both deterministic and stochastic environments, focusing on analyzing the persistence and stability of the populations. Here, we evaluate this premise in the framework of a consumer-resource interaction considering the energy investment towards reproduction vs. maintenance as a plastic trait according to positive/negative variation of the available resource. A basic consumer-resource mathematical model is formulated based on the principle of biomass conversion that incorporates the energy allocation toward vital functions of the life-cycle of consumer individuals. Our mathematical approach is based on the impulsive differential equations at fixed moments considering two impulsive effects associated with the instants at which consumers obtain environmental information and when energy allocation strategy change occurs. From a preliminary analysis of the non-plastic temporal dynamics, namely when the energy allocation is constant over time and without experiencing changes concerning the variation of resources, both the persistence and stability of the consumer-resource dynamic are dependent on the energy allocation strategies belonging to a set termed stability range. We found that the plastic energy allocation can promote a stable dynamical pattern in the consumer-resource interaction depending on both the magnitude of the energy allocation change and the time lag between environmental sensibility instants and when the expression of the plastic trait occurs.

[Prevalence of Chlamydia trachomatis infection and a potential perinatal impact in Chilean patients]. / Prevalencia de la infección por Chlamydia trachomatis y su potencial impacto perinatal en pacientes chilenas.

Chlamydia trachomatis is the most frequent bacterial sexually transmitted disease around the world. Estimated prevalence by WHO is 4,2% for women. Most cases are asymptomatic, but complications in fertility and during pregnancy are possible. The aim of this review is to describe the prevalence of C. trachomatis in Chilean studies using polymerase chain reaction (PCR) for detection, to describe the possible perinatal complications, to know recommendations about pregnancy screening in other countries, and to discuss the possibility of implementing in Chile.

Prevalencia de la infección por Chlamydia trachomatis y su potencial impacto perinatal en pacientes chilenas / Prevalence of Chlamydia trachomatis infection and a potential perinatal impact in Chilean patients

Resumen Chlamydia trachomatis es la infección de transmisión sexual bacteriana más frecuente en el mundo. Según datos de la Organización Mundial de la Salud, su prevalencia se estima alrededor de 4,2% en mujeres. Es una infección silente; sin embargo, puede desarrollar complicaciones en la fertilidad o durante el embarazo. El objetivo de esta revisión es describir la prevalencia de C. trachomatis en estudios recientes en Chile, que utilicen para su detección reacción de polimerasa en cadena (RPC), revisar las posibles complicaciones perinatales asociadas, conocer las recomendaciones de tamizaje en gestantes en otros países y discutir la necesidad de incluir en nuestro país un programa de tamizaje prenatal.

Abstract Chlamydia trachomatis is the most frequent bacterial sexually transmitted disease around the world. Estimated prevalence by WHO is 4,2% for women. Most cases are asymptomatic, but complications in fertility and during pregnancy are possible. The aim of this review is to describe the prevalence of C. trachomatis in Chilean studies using polymerase chain reaction (PCR) for detection, to describe the possible perinatal complications, to know recommendations about pregnancy screening in other countries, and to discuss the possibility of implementing in Chile.

Online hate network spreads malicious COVID-19 content outside the control of individual social media platforms.

We show that malicious COVID-19 content, including racism, disinformation, and misinformation, exploits the multiverse of online hate to spread quickly beyond the control of any individual social media platform. We provide a first mapping of the online hate network across six major social media platforms. We demonstrate how malicious content can travel across this network in ways that subvert platform moderation efforts. Machine learning topic analysis shows quantitatively how online hate communities are sharpening COVID-19 as a weapon, with topics evolving rapidly and content becoming increasingly coherent. Based on mathematical modeling, we provide predictions of how changes to content moderation policies can slow the spread of malicious content.

Hidden order across online extremist movements can be disrupted by nudging collective chemistry.

Disrupting the emergence and evolution of potentially violent online extremist movements is a crucial challenge. Extremism research has analyzed such movements in detail, focusing on individual- and movement-level characteristics. But are there system-level commonalities in the ways these movements emerge and grow? Here we compare the growth of the Boogaloos, a new and increasingly prominent U.S. extremist movement, to the growth of online support for ISIS, a militant, terrorist organization based in the Middle East that follows a radical version of Islam. We show that the early dynamics of these two online movements follow the same mathematical order despite their stark ideological, geographical, and cultural differences. The evolution of both movements, across scales, follows a single shockwave equation that accounts for heterogeneity in online interactions. These scientific properties suggest specific policies to address online extremism and radicalization. We show how actions by social media platforms could disrupt the onset and 'flatten the curve' of such online extremism by nudging its collective chemistry. Our results provide a system-level understanding of the emergence of extremist movements that yields fresh insight into their evolution and possible interventions to limit their growth.

Hidden resilience and adaptive dynamics of the global online hate ecology.

Online hate and extremist narratives have been linked to abhorrent real-world events, including a current surge in hate crimes1-6 and an alarming increase in youth suicides that result from social media vitriol7; inciting mass shootings such as the 2019 attack in Christchurch, stabbings and bombings8-11; recruitment of extremists12-16, including entrapment and sex-trafficking of girls as fighter brides17; threats against public figures, including the 2019 verbal attack against an anti-Brexit politician, and hybrid (racist-anti-women-anti-immigrant) hate threats against a US member of the British royal family18; and renewed anti-western hate in the 2019 post-ISIS landscape associated with support for Osama Bin Laden's son and Al Qaeda. Social media platforms seem to be losing the battle against online hate19,20 and urgently need new insights. Here we show that the key to understanding the resilience of online hate lies in its global network-of-network dynamics. Interconnected hate clusters form global 'hate highways' that-assisted by collective online adaptations-cross social media platforms, sometimes using 'back doors' even after being banned, as well as jumping between countries, continents and languages. Our mathematical model predicts that policing within a single platform (such as Facebook) can make matters worse, and will eventually generate global 'dark pools' in which online hate will flourish. We observe the current hate network rapidly rewiring and self-repairing at the micro level when attacked, in a way that mimics the formation of covalent bonds in chemistry. This understanding enables us to propose a policy matrix that can help to defeat online hate, classified by the preferred (or legally allowed) granularity of the intervention and top-down versus bottom-up nature. We provide quantitative assessments for the effects of each intervention. This policy matrix also offers a tool for tackling a broader class of illicit online behaviours21,22 such as financial fraud.

Emergent dynamics of extremes in a population driven by common information sources and new social media algorithms.

We quantify how and when extreme subpopulations emerge in a model society despite everyone having the same information and available resources - and show that counterintuitively these extremes will likely be enhanced over time by new social media algorithms designed to reduce division. We verify our analysis mathematically, and show it reproduces (a) the time-dependent behavior observed in controlled experiments on humans, (b) the findings of a recent study of online behavior by Facebook concerning the impact of 'soft' and 'hard' news, (c) the observed temporal emergence of extremes in U.S. House of Representatives voting, and (d) the real-time emergence of a division in national opinion during the ongoing peace process in Colombia. We uncover a novel societal tipping point which is a 'ghost' of a nearby saddle-node bifurcation from dynamical systems theory, and which provides a novel policy opportunity for preventing extremes from emerging.

New online ecology of adversarial aggregates: ISIS and beyond.

Support for an extremist entity such as Islamic State (ISIS) somehow manages to survive globally online despite considerable external pressure and may ultimately inspire acts by individuals having no history of extremism, membership in a terrorist faction, or direct links to leadership. Examining longitudinal records of online activity, we uncovered an ecology evolving on a daily time scale that drives online support, and we provide a mathematical theory that describes it. The ecology features self-organized aggregates (ad hoc groups formed via linkage to a Facebook page or analog) that proliferate preceding the onset of recent real-world campaigns and adopt novel adaptive mechanisms to enhance their survival. One of the predictions is that development of large, potentially potent pro-ISIS aggregates can be thwarted by targeting smaller ones.

First Report of Tobacco ringspot virus in Blackberry (Rubus sp.) in Alabama.

In 2006, primocane stunted growth and crumbly berry development were observed on 4-year-old Kiowa and Apache blackberry cultivars grown at the Chilton Research and Extension Center, Clanton, AL. Samples from affected plants were tested for virus infection by ELISA kits (Agdia, Inc., Elkhart, IN) specific to each of 14 different viruses. Most samples tested positive for Tobacco ringspot virus (TRSV). TRSV was detected in blackberry samples from North Carolina and South Carolina (2). Bray et al. (1) studied the incidence of viruses in blackberry nursery stock in the United States and reported that 9% of the tested samples contained TRSV. Thus, a survey was conducted for TRSV incidence among commercial blackberry stands in eight counties in Alabama during July 2007. Blackberry plants were observed to express virus-like symptoms including chlorotic spots on leaves, leaf veinal chlorosis, stunting, and combinations thereof. Fruit-bearing plants sometimes had crumbly fruit symptoms characteristic of virus infection. Leaf samples that were collected from symptomatic and nonsymptomatic plants representing 14 cultivars were tested by TRSV ELISA (Agdia, Inc.). Of 180 blackberry samples, 68 tested positive for TRSV. Positive ELISA reactions for TRSV were on average 28 times greater than the reactions of known negative control samples considered negative for TRSV. Blackberry plants shown to be infected with TRSV during the 2007 survey were tested in July 2008 in an effort to confirm the presence of TRSV. Fifty-four percent of the samples tested positive by ELISA with the average positive ELISA value being 21 times higher than the average negative ELISA value for known negative control samples. To further confirm the occurrence of TRSV in Alabama-grown blackberry plants, leaf samples were tested by reverse transcription (RT)-PCR to amplify a 329-bp fragment of the viral coat protein gene (TRSV RNA 2 sequence accession no. NC_005096; primers TRSCP-F (5'-TCTGGCACTATAAGCGGAAG-3') and TRSCP-R (5'-GAAAACATGGGAGGATGCAC-3'). A single band of the anticipated size was amplified (analyzed by agarose gel electorphoresis and visualized by ethidium bromide staining) from RNA samples extracted with a RNeasy Mini kit (Qiagen, Valencia, CA) from blackberry samples that tested positive for TRSV by ELISA and a known positive control. No amplified product resulted from a blackberry sample that tested negative for TRSV by ELISA. These results illustrate and confirm the presence of TRSV in blackberry leaf tissues grown in Alabama. To our knowledge, this is the first report of TRSV infection of blackberry plants in Alabama. References: (1) M. M. Bray et al. HortScience 40:874, 2005. (2) T. L. Guzmán-Baeny. Incidence, distribution, and symptom description of viruses in cultivated blackberry (Rubus subgenus Eubatus) in the southeastern United States. M.S. thesis, North Carolina State University, Raleigh, 2003.

An algorithm to locate hrB- donors for individuals with sickle cell disease.

Many African Americans with sickle cell disease (SCD) develop alloantibodies to antigens in the Rh blood group system. Others have shown that from D- individuals, those lacking the high-incidence hrB antigen (> 98% prevalence) may be found among r'r African Americans. We describe an algorithm to locate units for African Americans with SCD and anti-hrB and -D. From 46,539 donations, 5136 listed African American as race. Our primary reference laboratory performed Rh phenotyping (D, C, c, E, e) for first-time donors and those not tested previously. Specimens typing r'r were sent to a secondary reference laboratory for hrB phenotyping after each donation. Hemoglobin S screening was performed. Of 24 donors (27 donations) who phenotyped r'r, seven donors,29.2 percent (nine donations) were hrB-. Two of seven who donated twice consistently tested hrB-. One of 24 donors initially tested hrB-, but hrB+ on repeat donation. The donor tested hrB- by a second reference laboratory. Reagents for phenotyping high-incidence antigens are often not readily available, requiring a specialized reference laboratory that adds cost and turnaround time. Our algorithm selected r'r African American donors most likely to lack hrB for further evaluation by a second reference laboratory. We felt this was the most judicious use of resources and provided the greatest opportunity to find compatible components for individuals with SCD and anti-hrB and -D.

Confirmation of positive antibody screens by solid-phase red cell adherence assay using a tube technique method with polyethylene glycol enhancement.

Our blood bank routinely screens donors for antibodies using a solid-phase red cell adherence (SPRCA) assay. Positive results are then confirmed using a tube technique with polyethylene glycol (PEG) enhancement due to reported higher specificity than with SPRCA. Over a 5-month period, 49,084 donor serum or plasma samples were tested using the SPRCA assay. Further identification of positive samples was performed using a PEG enhancement method. Testing was performed with strict adherence to the manufacturers' inserts. Of 49,084 samples, 313 (0.64%) were positive by the SPRCA assay. Of these, 99 (31.6%) samples remained positive when tested with PEG enhancement. The remaining 214 (68.4%) were negative, giving specificity for the SPRCA assay of 99.6 percent (48,985/ 49,199). We report a high specificity for antibody screening using the SPRCA assay. However, it is cost effective to perform a confirmatory tube test with PEG enhancement because 214 SPRCA assay samples were interpreted as having a negative antibody screen, thus allowing the release of valuable blood components for transfusion.

Seroprevalencia del VIH en embarazadas de la maternidad "Percy Boland" en Santa Cruz - Bolivia año 1997 / Seroprevalencia of the V.I.H. in pregnant of the Maternidad Percy Boland in Santa Cruz - Bolivia, 1997

Para conocer la seroprevalencia del virus de la inmunodeficiencia humana (VIH) en embarazadas que asisten a su primer control prenatal en la meternidad "Percy Boland" se analizaron 630 muestras durante el periodo de abril a diciembre de 1997. Las muestras de suero recolectadas fueron procesadas a traves del metodo de Enzimoinmunoensayo (ELISA) para la detección de anticuerpos para el VIH1/2, en el laboratorio de Virología del CENETROP. Los resultados serológicos obtenidos de las 630 muestras analizadas, fueron no reactivos para el Test de ELISA para VIH. Este datos nos permite establecer con un nivel de confianza del95

Brote de fiebre amarilla selvatica en el departamento de Santa Cruz-Bolivia, año 1999 / Bud of wild Yellow Fever in departament of Santa Cruz - Bolivia, year 1999

Entre el mes de enero y abril de 1999 se presento un brote de fiebre amarilla selvatica en el departamento de Santa Cruz. CENETROP apoyo a la dirección departamental de salud procesando las muestras de suero recolectadas por el personal de epidemiologia. Se recibieron un total de 175 muestras para ser analizadas en el laboratorio de arbovirosis de CENETROP. De las 175 muestras 51 (29.1 por ciento) fueron positivas para fiebre amarilla. El material enviado a CENETROP principalmente por la Unidad Departamental de Epidemiologia y centros medicos asistenciales, consistio en muestras de suero de pacientes con manifestaciones clinicas compatibles con fiebre amarilla o necropsias de higado de los pacientes fallecidos con manifestaciones clinicas similares. En total se han confirmados por laboratorio 51 casos con 21 (41.2 x ciento) fallecidos. Se indica la regularidad temporal y geografica de los brotes, que deberia inducir actividades de control de programadas. Se destaca la observacion del 20 x ciento de los casos en niños entre 5 a 10 años de edad. Del total de casos el 33 x ciento fueron mujeres. Finalmente, se llama la atencion sobre el peligro de la ocurrencia de casos urbanos de fiebre amarilla, por la presencia de casos selvaticos que son trasladados a la ciudad en fase viremica y la alta infestacion domiciliaria por Aedes aegypti en la ciudad de Santa Cruz

Anomalías dentomaxilares en pacientes tratados quirúrgicamente portadores de labio leporino unilateral y fisura velopalatina / Dentomaxillary abnormalities in patients surgically treated with unilateral cleft lip and velopallatine fisure

De un total de 187 casos de pacientes portadores de labio leporino unilateral derecho o izquierdo y fisura velopalatina operados, provenientes del Instituto de Malformaciones y Deformaciones Máxilofaciales de la Facultad de Odontología de la Universidad de Chile, se seleccionó una muestra de 103 casos de ambos sexos, con edades entre 4 y 22 años. Se clasificaron según tipo de dentición y lado de la fisura. Con el propósito de describir las anomalías dentomaxilares que las caracteriza y determinar la frecuencia con que se presenta. El estudio se realizó sobre modelos y sus respectivas radiografías y/o periapicales antes de coemnzar el tratamiento ortodóncico. Se determinó que la fisura predominate es la izquierda. Al análisis en conjunto de modelos y radiografías se observó un mayor porcentaje de agenesias del incisivo lateral superior izquierdo, hecho directamente relacionado con el predominio de la fisura del lado izquierdo (61,17 por ciento), sobre la del lado derecho (38,83 por ciento). También se observaron agenesias de ambos laterales en 6,8 por ciento de los casos. Al estudiar la presencia de supernumerarios y su ubicación por segmentos se determinó que la mayoría presentaba supernumerarios, en Nº de 1 ó 2 y estos se ubicaban en los segmentos menores adyacentes a la fisura y en relación a los caninos. Con respecto al grado de giroversión sobre todo del incisivo vecino a la fisura no se encontró alineación normal en ninguno de los casos estudiados. En cuanto al estudio de la relación sagital de los modelos en oclusión en el sector posterior, el porcentaje mayor correspondió a la neutrooclusión, tanto a nivel molar como canina y en la zona anterior lo más frecuente fue el resalte invertido. Los resultados del análisis de la relación transversal mostraron que a nivel canino del lado comprometido predominó la mordida cruzada y a nivel del primer molar la relación transversal normal. El estudio de la desviación de la línea dental media superior en los modelos indicó que esta se presentaba desviada en un 76,70 por ciento. En sentido vertical predominó el escalón disminuido. Se hizo un estudio especial del escalón en la región de la fisura y este reveló que la mayor frecuencia se presentó en mordida abierta con 58,25 por ciento

Cerebrospinal fluid penetration of cefpirome in patients with non-inflamed meninges.

Twenty patients (mean age 52 +/- 12 years, mean weight 75 +/- 15 kg) scheduled for elective myelogram or spinal anaesthesia were enrolled to determine the cerebrospinal fluid (CSF) penetration of a new expanded spectrum cephalosporin antibiotic, cefpirome (HR-810). A single 2 g intravenous dose of cefpirome was administered as a bolus between 1 and 8 h before lumbar puncture. Blood samples were collected at 15 pre-determined times and a single CSF sample was obtained at the time of lumbar puncture. Serum and CSF cefpirome concentrations were determined by high performance liquid chromatography. The mean maximal serum concentration of cefpirome was 264 +/- 76 mg/L. A mean steady-state volume of distribution of 20 +/- 4 L, clearance of 7.4 +/- 1.3 L/h, and half-life of 2.5 +/- 0.5 h were determined. Mean CSF concentrations were 0.50 +/- 0.11 mg/L at 1-2 h post dose (n = 4), 0.57 +/- 0.13 mg/L at 2-4 h post dose (n = 4), 0.76 +/- 0.34 mg/L at 4-6 h post dose (n = 7), and 0.83 +/- 0.29 mg/L at 6-8.3 h post dose (n = 5). Blood:brain barrier permeability to cefpirome may not be a limiting factor as CSF concentrations were rapidly attained. Further studies are required to determine the mechanism of cefpirome transport between plasma and CSF.