Remote sensing of forest damage in the Czech Republic using hyperspectral methods

The current study assesses the potential of hyperspectral data for monitoring the initial stages of damage in Norway spruce forests characterized by subtle changes in foliar chlorophyll and chemistry. Both field and airborne high spectral resolution reflectance measurements were obtained for selected study sites in the Krusne hory, Czech Republic. High spectral resolution airborne canopy data and field foliar samples were acquired simultaneously in August 1998 for a total of 51 study sites within the Krusne hory. The sites were selected to represent a full range of damage conditions in even-aged Norway spruce (Picea abies (L.) Karst) stands located between 820--920m elevation. Reflectance, foliar pigments, nitrogen and chemical constituents were determined for first-, second- and third-year needles. A strong correlation to damage was established for the foliar chemistry. A significant increase in polar compounds (such as tannins, sugars and starch) and a reduced needle lignification occurs with increasing damage. Foliar chemical constituents appear to be effective indicators of long-term environmental conditions. The strong relationship between damage level and polar compounds suggests high potential for use of these constituents as bio-indicators of stress. Both field and airborne high spectral resolution data separate the initial forest damage classes. Based on field reflectance measurements for third-year needles, derivative indices from the red edge region were most strongly correlated to damage level, followed by indices ratioing damage-sensitive and damage-insensitive bands and a parameter describing the fit of an Inverted Gaussian curve. Red/red edge spectral data from the Airborne Solid State Array Spectrometer (ASAS) had the highest potential for separation of initial levels of damage, which corresponds with the region suggested as most sensitive to damage as seen in conducting the field reflectance measurements. Both optical and derivative indices incorporating reflectance from the red edge region present the most potential as indicators of initial damage in both leaf and canopy spectra

Generation and escape of local waves from the boundary of uncoupled cardiac tissue

We aim to understand the formation of abnormal waves of activity from myocardial regions with diminished cell-to-cell coupling. In route to this goal, we studied the behavior of a heterogeneous myocyte network in which a sharp coupling gradient was placed under conditions of increasing network automaticity. Experiments were conducted in monolayers of neonatal rat cardiomyocytes using heptanol and isoproterenol as means of altering cell-to-cell coupling and automaticity respectively. Experimental findings were explained and expanded using a modified Beeler-Reuter numerical model. The data suggests that the combination of a heterogeneous substrate, a gradient of coupling and an increase in oscillatory activity of individual cells creates a rich set of behaviors associated with self-generated spiral waves and ectopic sources. Spiral waves feature a flattened shape and a pin-unpin drift type of tip motion. These intercellular waves are action-potential based and can be visualized with either voltage or calcium transient measurements. A source/load mismatch on the interface between the boundary and well-coupled layers can lock wavefronts emanating from both ectopic sources and rotating waves within the inner layers of the coupling gradient. A numerical approach allowed us to explore how: i) the spatial distribution of cells, ii) the amplitude and dispersion of cell automaticity, iii) and the speed at which the coupling gradient moves in space, affects wave behavior, including its escape into well-coupled tissue.Comment: 28 pages, 10 figures, submitted to Biophysical Journa

Approche interprétative à l interaction entre culture et langage : « La culture devient ainsi un « tool-kit », une boîte à outils qui sert de support pour donner sens à la réalité, la langue étant l outil le plus important. » (Bruner 2015 cité par Britt-Mari Barth : 5)

Kieli on ihmisten tapa rakentaa todellisuutta. Inhimillinen kieli on tavattoman monimuotoinen ja kykeneväinen ilmaisemaan paljon laajempia kokonaisuuksia kuin eläinten viestintäjärjestelmät. Kielen kehitys on yhtäältä sidoksissa yksilön kognitiivisten, affektiivisten, psykomotoristen ja sosiaalisten kykyjen kehitykseen ja toisaalta kulttuurisiin seikkoihin. Tutkimuksessani analysoin lapsen kielen kehitykseen yhtenä tekijänä vaikuttavien lorujen ja laulujen merkitystä kielellisen hahmottamisen kannalta. Kielen omaksumista on tutkittu paljon, mutta lapsille osoitettuja ja lasten käyttämien leikkimielisten kieliaineistojen tutkimus on jäänyt taka-alalle mekanistisempien oppimismekanismien analyysin tieltä. Perustan tutkimukseni metodologisen aineksen osalta ennen kaikkea psykolingvistiseen tutkimukseen (Piaget, Vygotski, Bruner, jne.), joka on viime vuosina painottanut lapsen ensimmäisten ikävuosien merkitystä kielelliselle kehitykselle. Perimmäisenä pyrkimyksenä on etsiä vastausta siihen, miten kielellinen ilmaisu kuvaa yhteiskunnan asennetta pienimpiä jäseniään kohtaan. On selvää, että yhtenä keskeisenä elementtinä lapsen kielen kehityksessä on suhde vanhempiin/hoitajiin ja heidän kanssaan muotoutuva interaktiivinen kommunikaatio. Tutkielmani korpus koostuu kansanperinteen piiriin kuuluvista teksteistä neljällä eri kielellä (ranska, espanja, suomi, bulgaria). Lorut, leikit, laulut, pirileikit, jne., ovat kehittäneet lapsen kykyä mieltää itsensä osaksi yhteisöä ja sen kulttuuriperintöä ja siten edesauttaneet myös kielellistä kehitystä. Merkittävä osa lapsuuden ajan kognitiivisista prosesseista ovat tukena myöhemmille päämäärään tähtääville toiminnoille. Korpukseni 31 tekstistä 7 on ranskan-, 9 suomen-, 8 espanjan ja 7 bulgariankielisiä. Kaikissa näissä teksteissä, kielestä riippumatta, on yhteisiä elementtejä kuten esimerkiksi toistoa, luettelointia, loppusointuja, assonansseja ja alkusointuja. Niiden perimmäisenä tarkoituksena on mnemoteknisiä keinoja käyttäen opettaa lapsi hahmottamaan ympäröivää yhteiskuntaa ja itseään sen osana. Olen kiinnittänyt erityistä huomiota ns. sormileikkeihin, joissa usein yhdistyvät leikki, loru ja laulu. Yhteisten piirteiden rinnalla on myös tekstejä toisistaan erottavia elementtejä. Analysoimistani teksteistä voi havaita mm., että suomalaisissa lastenloruissa on usein pelottavia piirteitä, kun taas ranskalaisia ja espanjalaisia loruja leimaa tietty kepeys. Mitä puhtaasti kielellisiin seikkoihin tulee, niin ranskan- ja espanjankieliset tekstit erottuvat muista kompleksisemman syntaksinsa kautta, kun taas suomalaisia tekstejä leimaa monimuotoinen äännemaailma. Bulgarialaisten tekstien silmiinpistävä ominaisuus taas on niiden leikkimielisyys. Korpuksen teksteissä havaittavat erot kuvaavat todennäköisesti hyvinkin merkittäviä eroja kunkin kulttuurin ominaispiirteiden välillä. Lapset oppivat oman kulttuurinsa erityispiirteet kielen kautta, minkä vuoksi lorut, laulut ja leikit valmistavat lapsia toimimaan oman kulttuurinsa perusperiaatteiden mukaan. On selvää, että tutkimukseni ei laajuudeltaan ole riittävä laajojen yleistyksien tekemistä varten. Analyysini osoittaa kuitenkin suppeudestaan huolimatta, että kielelliset ja kulttuuriset erot ovat keskeisessä asemassa lapsen kehittyessä yhteisönsä jäseneksi. Ne valottavat myös kiinnostavasti kulttuurisia erikoispiirteitä ja sitä, mitä kussakin yhteisössä pidetään arvokkaana. Uusia tutkimusmahdollisuuksia tällä saralla on huomattavan paljon

Cardiac Cellular Coupling and the Spread of Early Instabilities in Intracellular Ca2+

AbstractRecent experimental and modeling studies demonstrate the fine spatial scale, complex nature, and independent contribution of Ca2+ dynamics as a proarrhythmic factor in the heart. The mechanism of progression of cell-level Ca2+ instabilities, known as alternans, to tissue-level arrhythmias is not well understood. Because gap junction coupling dictates cardiac syncytial properties, we set out to elucidate its role in the spatiotemporal evolution of Ca2+ instabilities. We experimentally perturbed cellular coupling in cardiac syncytium in vitro. Coupling was quantified by fluorescence recovery after photobleaching, and related to function, including subtle fine-scale Ca2+ alternans, captured by optical mapping. Conduction velocity and threshold for alternans monotonically increased with coupling. Lower coupling enhanced Ca2+ alternans amplitude, but the spatial spread of early (<2 Hz) alternation was the greatest under intermediate (not low) coupling. This nonmonotonic relationship was closely matched by the percent of samples exhibiting large-scale alternans at higher pacing rates. Computer modeling corroborated these experimental findings for strong but not weak electromechanical (voltage-Ca2+) coupling, and offered mechanistic insight. In conclusion, using experimental and modeling approaches, we reveal a general mechanism for the spatial spread of subtle cellular Ca2+ alternans that relies on a combination of gap-junctional and voltage-Ca2+ coupling

Contribution of Chlorophyll Fluorescence to the Apparent Reflectance of Vegetation

Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance (R) measurements, whi ch provide estimates of relative vegetation vigor based primarily on chlorophyll content. Vegetation chlorophyll fluorescence (CF) offers a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, monitoring of vegetation vigor based on CF may allow earlier stress detection and more accurate carbon sequestra tion estimates, than is possible using R data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contrib utions from both the reflected and fluoresced radiation. The aim of t his study is to determine the relative R and CF fractions contributing to Ra from the vegetation in the red to near-infrared region of the spectrum. The practical objectives of the study are to: 1) evaluate t he relationship between CF and R at the foliar level for corn, soybean, maple; and 2) for corn, determine if the relationship established f or healthy (optimal N) vegetation changes under N defiiency. To obtai n generally applicable results, experimental measurements were conducted on unrelated crop and tree species (maple, soybean and corn), unde r controlled conditions and a gradient of inorganic N fertilization l evels. Optical R spectra and actively induced CF emissions were obtained on the same foliar samples, in conjunction with measurements of p hotosynthetic function, pigment levels, and C and N content. The comm on spectral trends or similarities were examined. On average, 10-20% of apparent R at 685 nm was actually due to CF. The spectral trends in steady and maximum F varied significantly, with Fs (especially red) showing higher ability for species and treatment separation. The relative contribution of ChF to R varied significantly among species, with maple emitting much higher F amounts, as compared to corn and soybea n. Fs individual red and far-red bands and their ratio exhibited consistent species separations. For corn, the relative CF fraction increased in concert with the nutrient stress levels from 7% for severely nutrient deficient plants. F685s provide d optimal treatment separation. This study confirms the trends in F68 5sE740s associated with N deficiency and vegetation stress, established usmg single narrow band excitation

Opto-SICM framework combines optogenetics with scanning ion conductance microscopy for probing cell-to-cell contacts

We present a novel framework, Opto-SICM, for studies of cellular interactions in live cells with high spatiotemporal resolution. The approach combines scanning ion conductance microscopy, SICM, and cell-type-specific optogenetic interrogation. Light-excitable cardiac fibroblasts (FB) and myofibroblasts (myoFB) were plated together with non-modified cardiomyocytes (CM) and then paced with periodic illumination. Opto-SICM reveals the extent of FB/myoFB-CM cell-cell contacts and the dynamic changes over time not visible by optical microscopy. FB-CM pairs have lower gap junctional expression of connexin-43 and higher contact dynamism compared to myoFB-CM pairs. The responsiveness of CM to pacing via FB/myoFB depends on the dynamics of the contact but not on the area. The non-responding pairs have higher net cell-cell movement at the contact. These findings are relevant to cardiac disease states, where adverse remodeling leads to abnormal electrical excitation of CM. The Opto-SICM framework can be deployed to offer new insights on cellular and subcellular interactions in various cell types, in real-time

Sex-dependent transcription of cardiac electrophysiology and links to acetylation modifiers based on the GTEx database

Development of safer drugs based on epigenetic modifiers, e.g., histone deacetylase inhibitors (HDACi), requires better understanding of their effects on cardiac electrophysiology. Using RNAseq data from the genotype-tissue-expression database (GTEx), we created models that link the abundance of acetylation enzymes (HDAC/SIRT/HATs), and the gene expression of ion channels (IC) via select cardiac transcription factors (TFs) in male and female adult human hearts (left ventricle, LV). Gene expression data (transcripts per million, TPM) from GTEx donors (21–70 y.o.) were filtered, normalized and transformed to Euclidian space to allow quantitative comparisons in 84 female and 158 male LVs. Sex-specific partial least-square (PLS) regression models, linking gene expression data for HDAC/SIRT/HATs to TFs and to ICs gene expression, revealed tight co-regulation of cardiac ion channels by HDAC/SIRT/HATs, with stronger clustering in the male LV. Co-regulation of genes encoding excitatory and inhibitory processes in cardiac tissue by the acetylation modifiers may help explain their predominantly net-neutral effects on cardiac electrophysiology. ATP1A1, encoding for the Na/K pump, represented an outlier—with orthogonal regulation by the acetylation modifiers to most of the ICs. The HDAC/SIRT/HAT effects were mediated by strong (+) TF regulators of ICs, e.g., MEF2A and TBX5, in both sexes. Furthermore, for male hearts, PLS models revealed a stronger (+/-) mediatory role on ICs for NKX25 and TGF1B/KLF4, respectively, while RUNX1 exhibited larger (-) TF effects on ICs in females. Male-trained PLS models of HDAC/SIRT/HAT effects on ICs underestimated the effects on some ICs in females. Insights from the GTEx dataset about the co-expression and transcriptional co-regulation of acetylation-modifying enzymes, transcription factors and key cardiac ion channels in a sex-specific manner can help inform safer drug design

Computational Optogenetics: Empirically-Derived Voltage- and Light-Sensitive Channelrhodopsin-2 Model

Channelrhodospin-2 (ChR2), a light-sensitive ion channel, and its variants have emerged as new excitatory optogenetic tools not only in neuroscience, but also in other areas, including cardiac electrophysiology. An accurate quantitative model of ChR2 is necessary for in silicoprediction of the response to optical stimulation in realistic tissue/organ settings. Such a model can guide the rational design of new ion channel functionality tailored to different cell types/tissues. Focusing on one of the most widely used ChR2 mutants (H134R) with enhanced current, we collected a comprehensive experimental data set of the response of this ion channel to different irradiances and voltages, and used these data to develop a model of ChR2 with empirically-derived voltage- and irradiance- dependence, where parameters were fine-tuned via simulated annealing optimization. This ChR2 model offers: 1) accurate inward rectification in the current-voltage response across irradiances; 2) empirically-derived voltage- and light-dependent kinetics (activation, deactivation and recovery from inactivation); and 3) accurate amplitude and morphology of the response across voltage and irradiance settings. Temperature-scaling factors (Q10) were derived and model kinetics was adjusted to physiological temperatures. Using optical action potential clamp, we experimentally validated model-predicted ChR2 behavior in guinea pig ventricular myocytes. The model was then incorporated in a variety of cardiac myocytes, including human ventricular, atrial and Purkinje cell models. We demonstrate the ability of ChR2 to trigger action potentials in human cardiomyocytes at relatively low light levels, as well as the differential response of these cells to light, with the Purkinje cells being most easily excitable and ventricular cells requiring the highest irradiance at all pulse durations. This new experimentally-validated ChR2 model will facilitate virtual experimentation in neural and cardiac optogenetics at the cell and organ level and provide guidance for the development of in vivo tools

Adjuvant Treatment in Colon Cancer

Worldwide, more than 1 million people develop colorectal cancer (CRC) annually. CRC is a major health problem in the Western world and the second most common cause of cancer mortality. To improve performance, the role of chemotherapy for CRC has increased dramatically over the last decade. The vast majority of CRC patients now receive chemotherapy with multiple agents that are currently approved for the treatment in the appropriate setting [1]. However, it is a complex process to select the optimal chemotherapy for each patient and practice evidence gap is still a problem. Some guidelines for the treatment of CRC have been developed to promote the standardization of CRC treatment. Postoperative, or “adjuvant,” systemic therapy has become standard for stage III colon cancer. Adjuvant therapy should also be strongly considered in stage II patients. It is generally recommended for any medically fit patient with stage II cancer with unfavorable factors. The hypothesis that the antitumor activity of the combination agent, including oxaliplatin, irinotecan, bevacizumab, cetuximab in metastatic cure rates, would result in increased adjuvant proved to be often wrong. Although new drug development takes years, targeted drug use can occur more quickly with advanced tests and will be a focus of future work. In addition, efforts will focus on identifying biomarkers that predict response to systemic therapy so that tailored therapy can be initiated. The future of oncology will come with the better understanding of the biology and genetics of the tumor and its host. This will help to develop tailored approach to the patients, including more specific systemic therapy, aimed at molecular targets of the malignant tumor, thus reducing the negative effects. At that time, the treatment of oncological diseases will experience a new era, comparable to the introduction of antibiotics

Philanthropy and COVID-19 in the First Half of 2020

The rapid spread of COVID-19 has created a global health and economic crisis that is testing regions around the world. In response, foundations, corporations, and individuals have been disbursing funds to nonprofits to help communities cope with these unprecedented challenges. Candid has been closely tracking the global private philanthropic response to COVID-19 through news stories and other publicly available resources as well as from funders who have reported disbursements directly to Candid. In this report, the Center for Disaster Philanthropy and Candid look at the philanthropic dollars that were distributed for COVID-19 in the first half of 2020